- Email: [email protected]
Behavioral Adaptation of Floor-Reared White Leghorn Pullets to Different Cage Densities and Cage Shapes During the Initial Settling-in Period1
Behavioral Adaptation of Floor-Reared White Leghorn Pullets to Different Cage Densities and Cage Shapes During the Initial Settling-in Period 1 K. E. ANDERSON, A. W. ADAMS, and J. V. CRAIG Department of Animal Sciences and Industry, Kansas State University, Manhattan, Kansas 66506 (Received for publication March 1, 1988)
1989 Poultry Science 6 8 : 7 0 - 7 8 INTRODUCTION
have shown that deviations from linear hierarchies are common. Guhl (1958) determined that flocks that were assembled immediately after hatching developed a social structure in 8 to 10 wk. Development of a peck order after assembly in floor pens of small flocks of chickens, all of which are strangers, occurs in a period of time when aggression levels are highest. Guhl (1953) and Williams et al. (1977) reported that social interactions for small groups of chickens in floor pens were highest at initial assembly and generally declined and reached a plateau by 10 days postassembly. Their data indicated that the time needed to integrate into a social group was much less than Murchison (1936) originally proposed. Schelderuppe-Ebbe (1922), Guhl and Allee (1944), and Duncan et al. (1978) provided indirect evidence that hens introduced into socially organized flocks had reduced feed consumption, body weight, and general loss of condition until they had been assimilated into the flock. In contrast, Adams (1974) as well as Hester and Wilson (1986) concluded that introduction of hens into a small group of hens will not reduce performance.
The housing of a floor-reared pullet in a multiple-hen layer cage presents a drastic change in environment. During this period of adaptation or "settling-in" stage, pullets have to adapt to the new physical environment of high density cages that usually includes different styles of feeders and waterers, and strange cage mates. Information is limited on the behavior of pullets during the first few days posthousing in cages. Murchison (1936) examined the time function in the establishment of social hierarchies of the domestic fowl and proposed that individuals in pens of 2, 3, 4, 5, and 6 hens would need 15, 19, 22, 26, and 32 wk, respectively, to establish a linear peck order. His proposal that a "linear" hierarchy would develop was contrary to the findings of Schelderuppe-Ebbe (1922), who showed that nonlinear hierarchies were frequent. Other researchers, Guhl (1953), Craig (1986), and Craig and Ramos (1986) also
'Contribution 88-263-J from the Kansas Agricultural Experiment Station.
70
Downloaded from http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
ABSTRACT Two groups of White Leghorn pullets, reared in floor pens, were observed for changes in behavioral traits when housed in cages. Data in Experiment 1 were obtained during Days 1 to 5 posthousing from 40 pullets kept in eight 40.7-cm wide x 45.7-cm deep cages with either four or six birds/cage and in Experiment 2 during Days 1 to 5 and Day 7 posthousing from 24 pullets housed four/cage in three 30.5-cmwide x 45.7-cm deep cages (deep cages), and three 45.7-cm wide x 30.5-cm deep cages (shallow cages). In Experiment 1, pullets housed four/cage spent significantly (P<.05) fewer periods standing and crouching, but more periods preening, feeding, and performing comfort movements, than those housed six/cage. There was a significant group size x days posthousing interaction for standing and drinking. Standing was most frequent in the four-hen cages on Day 1 and then declined, whereas periods of standing increased in six-bird cages. Drinking behaviors were significantly different only on Day 1; six birds per cage had the lowest level. In Experiment 2, pullets in deep cages spent significantly more periods standing and moving and fewer periods crouching. Crouching frequencies declined from Day 1 to Day 7 posthousing for birds in both deep and shallow cages. Although there were significant cage shape x days posthousing interactions for all behavior observed, the interactions appeared to be associated with erratic day-to-day differences between hens in deep and shallow cages. (Key words: cage shape, density, settling in behavior)
ADAPTATION OF FLOOR-REARED PULLETS TO CAGES
MATERIALS AND METHODS
Experiment 1. In the rearing phase, egg type pullets (Craig etal., 1982) of the Y2 experimental strain were wing banded, sexed, and assigned randomly to four rearing pens with approximately 125 chicks each at 1 day of age. Pens were in a curtain-sided, naturally ventilated, brooding-rearing house. Supplemental heat was provided by natural gas-fired brooders. The standard Kansas State University feeding regimen, vaccination, and beak trimming procedures were followed (Anderson, 1987). Birds, hatched on June 17, were reared under naturally decreasing day lengths. Two cage environments were used: 1) four birds/cage with 464 cm2 floor area and 10.2 cm feeder space/pullet, which meets minimum space requirements as established in Great Britain by the Ministry of Agriculture, Fisheries, and Food (1971) and 2) six birds/cage with 310 cm2 floor area and 5.1 cm feeder space/bird, which is consistent with minimum space requirements recommended by United Egg Producers (1982) in the US. A common commercial layer cage was used; hens were placed in cages to meet recommended minimum space requirements per hen. As a result, group size and area per bird were confounded. Cages were adjacent in the row to facilitate simultaneous video recording. All cages were 45.7 cm deep X 40.64 cm wide with a continuous-flow water trough at the back of the cage. Feeder space in six-bird cages was restricted by blocking out 5.1 cm of
feeder space at each end with wooden blocks. Surrounding cages were populated to give an environment similar to that of a commercial layer facility. Video observations of settling-in behaviors were made to determine initial adaptation of pullets to the two environments. Twenty pullets were selected randomly from rearing pens at 146 and another 20 at 153 days of age in a way that ensures that as many as possible of the birds were strangers to each other. Because the pullets were reared on decreasing day lengths and no egg production occurred, the age difference of 7 days was thought to have little effect on the behavior observed. Birds were marked for identification by applying different colors to their back feathers before they were placed in cages. Settling-in behavior was observed during Days 1 through 5 posthousing. Birds had received about 12 h natural light in the broodingrearing house just prior to caging and were exposed to 12 h light/day during video recording. All feeding and care was done during the dark hours and the building was locked during the day to minimize disturbance. Observation equipment included two time-lapse recorders with built-in time-date display and two video cameras. The tapes were viewed using a recorder and large-screen monitor. Behaviors evaluated were: standing (otherwise inactive); crouching (off feet); preening; moving (walking and attempting to run or fly); feeding (pecking movements at feed in the trough); drinking; comfort (movements such as stretching and feather fluffing); pecking inedible objects other than feathers; and feather pecking. Other behaviors were observed, but their incidences were so low that analysis was not appropriate. A scanning technique (Anderson et al., 1985) was used for viewing the tapes. Filming was done using a 12-h mode on the recorder. Viewing was done at six times normal speed (2-h mode), i.e., scans were made every 180 s of actual time, providing 30 s of viewing time. Within this 30-s period, each chicken was observed for approximately 5 s and the behavior seen was recorded. Pullets were viewed in the same order in each scanning period. Tapes were viewed by two trained observers in a random order to avoid any biases. Experiment 2. In the rearing phase, approximately 1,800 day-old chicks of a commercial strain (Hyline W-77) were obtained from a local hatchery. Rearing practices were the same as in Experiment 1 except the chicks were fed either
Downloaded from http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
Schelderuppe-Ebbe (1922) determined that birds work out a social structure in which they discriminate between individuals. Syme et al. (1984) further stated that hens associate to a greater degree with lower or equally ranked birds within the group. This allows the birds to acquire their essential needs without attack or threats from higher ranked individuals. Cunningham and Van Tienhoven (1984) reported that the presence of higher ranking hens decreased egg production of the low ranking birds in multiple-bird cages. This effect was reduced by using shallow instead of deep cages, ad libitum rather than restricted feeding, and more space per hen. The objective of the experiments reported here was to determine the amount of time spent in various behaviors of floor-reared pullets as they settled into cage environments with different cage shapes and numbers of birds per cage.
71
ANDERSON ET AL.
72
RESULTS AND DISCUSSION
Experiment 1. Group size had significant (P< .05) effects on the amount of standing, crouching, preening, feeding, and comfort movements during the first 5 days posthousing in layer cages (Table 1). Hens housed four/cage spent significantly less time standing than hens housed six/ cage. Time spent standing was relatively constant over the first 5 days posthousing with a slight, but significant (P<.05) decrease during Days 2 and 3, followed by a return to the original level by Day 5. Examination of data for group size X days posthousing (Table 2) indicate that hens housed four/cage actually had more standing on Day 1, but reduced frequency of standing thereafter as compared with those housed six/ cage. Crouching, which may be an indication of fearfulness (Duncan et al., 1978), was signifi-
cantly (P< .05) lower with four hens/cage than with six/cage (Table 1). Crouching behavior declined significantly over days posthousing, suggesting that hens became less fearful, which allowed more time for other behaviors. The results indicate that group size does have an effect on development of the bird's initial behavior pattern. Standing and crouching had significantly lower frequencies in the smaller group size. Crouching may be the best single indicator of adaptation, being higher on Day 1 posthousing and then declining throughout the first 4 days. Significantly (P<.05) greater preening of hens housed four per cage (Table 1) suggests that hens housed six per cage may not have had sufficient space to perform grooming freely. Preening tended to increase after the 1st day, which may indicate a lower level of stress on the bird. Feeding activity was significantly more frequent in four-hen cages than in six-hen cages (Table 1). This may have been the result of availability of feeder space to the different hen populations. Hens in the four-bird cages could feed simultaneously, whereas those in the sixhen cages had to compete for access to the feeder. Feeding activity was lowest on Day 1, possibly because of unfamiliarity with the environment. Feeding activity then increased and leveled off over the remaining 4 days. Comfort activity also showed a significant difference associated with group size, with four hens/cage performing more comfort type behaviors than with six/cage. This may have been the result of the increased space per hen in the four-hen cages, which allowed for more activity. Pecking inedible objects increased over Days 1 and 2, then reached a plateau on the remaining days. Means for group size x days posthousing interactions for standing and drinking behaviors are presented in Table 2. Periods of standing of hens in four-bird cages were significantly more frequent on Day 1, then dropped to frequencies lower than those of pullets in six-bird cages on subsequent days. Levels of drinking activity were significantly different for group sizes on Day 1 only, with hens housed four/cage drinking more than those housed six/cage. Diurnal feeding patterns during hours when caretakers were absent were similar for pullets in both four and six-bird cages. Feeding activity levels shown in Figure 1 were highest over the first 4 h after lights were turned on (0600 h), then stayed at a plateau at a lower level over
Downloaded from http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
the standard Kansas State University step-down protein regimen or a step-up protein regimen (Anderson, 1987). At 18 weeks of age, a random sample of 12 pullets from each feeding regimen was housed in three adjacent cages, four birds/ 30.5 X 45.7-cm (deep) or 45.7 X 30.5-cm (shallow) cage located in two center rows of double-deck cages in a curtain-sided, naturally ventilated house. Pullets had 348 cm2 floor area and 7.6 or 11.4 cm feeder space/bird, respectively, in deep and shallow cages. Settling-in behavior was video recorded during Days 1 through 5 and on Day 7 posthousing. Birds had received 15 h supplemental light in the brooding-rearing house just prior to caging and were exposed to 15 h light/day during filming. All feeding was done at 1000 h and egg collection at 1300 h, so that day-to-day comparisons would be comparable in terms of disturbance by humans. Filming was done using the 24-h mode on the recorder. Observation techniques were the same as in Experiment 1 except that viewing was done at 12 times normal speed (2-h mode). Using the scanning technique, a 180-s actual time period was viewed in 15 s. Data were pooled for the birds housed at 146 and 153 days of age and then summarized on an hourly basis for each day posthousing. Data were then subjected to the ANOVA procedure with a split-split-plot design over days posthousing with repeated measures over hours within days. Means for days and hours were tested by least significant differences when significant differences were present.
5.0 a 4.2 b 4.0 b 3.4C 3.4C
5.5 a 4.9 b 4.9 b 5.1ab 5.5 a
1 2 3 4 5
Days posthousing (DPH)
Means within columns with no common superscripts differ significantly (P<.05).
2.8 a 3.1ab 3.5 b c 3.7C 3.3abc
3.9* 2.9
Preening 1.3 1.2 12ab 1.2 ab 12ab 1.4a l.lb
Moving
4.0 a 4.9b 4.9 b 4.7b 4.8b
5.0* 4.5
Feeding
PI = Pecking inedible objects; FP = feather pecking.
**P<.01.
*P<.05.
2
Table values are number of 3-min periods/h behavior was observed per pullet. Each pullet was observed 30 s/3-m 464 cm2 floor area and 10.2 cm feeder space/pullet or six birds/cage, with 310 cm2 floor area and 5.1 cm feeder space/p
1
GX DPH
3.3* 4.5
4.9* 5.4
4 hens 6 hens
Group size (G)
Crouching
Standing
Treatment
Parameter
TABLE 1. Effect of group size and days posthousing on "settling in " behaviors, Ex
om http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
ANDERSON ET AL.
74
10 3
-o- 4 Hens/Cage -•- 6 Hens/Cage
8-
o
I "5S
o 0)
a 4c
i — i —
— i —
8 10 12 14 Hours Within the Day
16
18
FIGURE 1. Diurnal pattern of feeding comparing four vs. six hens/cage during the "settling in" period. Birds were housed four birds/cage with 464 cm2 floor area and 10.2 cm feeder space/pullet or six birds/cage, with 310 cm2 floor area and 5.1 cm feeder space/pullet.
higher level on Days 5 and 7, which seems to indicate adaptation to the environment. In shallow cages feeding activity was greater on Day 2 than on Day 1; however, it dropped at Day 3 and began a slow increase through Day 7. This difference in feeding activity in deep vs. shallow cages may have resulted from less competition at the feeder in shallow cages. Guhl (1953) noted that aggression occurs when birds are competing for resources of feed, water and space. This may have been the reason for changes in feeding
TABLE 2. Treatment means for behaviors in which group size interacted with days posthousing. Experiment
1'
Behavior
Days p o s t h o u s i n g
4 pu Uets/cage
6 pullets/cage
Difference
Standing
1 2 3 4 5
5.9 4.5 4.6 4.6 4.9
5.2 5.2 5.0 5.5 5.9
.7* -.7* -.4 -.9* -1.0*
Drinking
1 2 3 4 5
.6 .7 .7 .7 .8
.4 .7 .6 .7 .8
.2** .0 .1 .0 .0
1 Birds were housed four birds/cage with 464 cm2 floor area and 10.2 cm feeder space/pullet or six birds/ cage, with 310 cm2 floor area and 5.1 cm feeder space/pullet.
*P<.05. **P<.01.
Downloaded from http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
the next 5 h; levels were not significantly different until 1400 h. Feeding periods were fairly constant during the middle of the day, then increased moderately until 1 h prior to lights out (1700 h). Periods of feeding declined sharply during the last hour before darkness. This pattern is similar to that found by Hughes and Black (1977), who reported the same general diurnal pattern of feeding, but without the sharp decline during the last hour. Experiment 2. Cage shape caused significant differences in behavior patterns. Pullets in deep cages spent significantly (P<.05) more frequent periods standing than those in the shallow cages (Table 3) during all six observation days posthousing except Day 5 (Table 4). The overall higher incidence of standing in deep cages may have resulted from greater competition for feeder space in those cages. Hens in shallow cages also spent less time moving. This may have been the result of the greater feeder space allowed per hen in the shallow cage. Birds housed in both deep and shallow cages fed the same number of periods per hour during the settling-in period (Table 3). There were significant cage shape x days posthousing interactions for all behaviors observed (Table 3). Feeding activity was generally greater after Day 1 in deep cages, possibly because of greater fearfulness associated with unfamiliarity with the environment on Day 1. Feeding activity increased the following day, most likely because of increasing hunger. Feeding activity appeared to reach a plateau at a
*
** *
*
*
*
PI = Pecking inedible objects; FP = feather pecking.
***P<.001.
**P<.01.
*P<.05.
2
'Table values are number of 3-min periods/h behavior was observed per pullet. Each pullet was observed 30 s/3-min 45.7-cm (deep) or 45.7 X 30.5-cm (shallow) cages with 7.6 or 11.4 cm feeder space/hen, respectively.
Means within columns with no common superscripts differ significantly (P<.05).
S X DPH
3.8 3.5 4.4 4.6
42
3 6
.8a .8a .8a 1.0 a .8a .8a
1.2 d 2.0 C 2.5ab 2.6a 2.7a 2.3bc
8.9a 8.5a 7.5b 7 2 b c 6.9bc 6.5C
4.1a 3.0 C 3.5bc 4.1ab 3.6abc 3.9ab
1 2 3 4 5 7
D a y p o s t h o u s i n g (DPH)
4.0 4.0
1.0* .6
2.5 2.0
6.4* 8.8
4.5* 2.8
Deep Shallow
Shape (S)
Fee
Moving
Crouching
Standing
Treatment
Parameter
Preening
TABLE 3. Effect of cage shape and days posthoustng on "settling in" behaviors, Ex
om http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
ANDERSON ET AL.
76
activity over time, although little aggression was observed. Recent studies by Banks etal. (1979), Craig and Ramos (1986), and review articles by Syme (1974) and Craig (1986) raise questions about acceptance of such general assumptions.
Standing was more frequent on Day 1 than on Days 2 and 3, but was not significantly different from that on Days 4, 5, and 7 (Table 3). The greater standing activity of the deep-caged birds (Table 4) may have been due to the fre-
TABLE 4. Treatment means for' behaviors in which cage shape interacted with day posthousing, Experiment 2 Cage shape 1 Days posthousing
Deep
Shallow
Standing
1 2 3 4 5 7 1 2 3 4 5 7
5.1 4.0 4.6 4.6 3.9 5.1 7.5 7.7 5.5 6.5 5.7 5.3
3.1 2.0 2.3 3.5 3.4 2.7 10.4 9.3 9.5 7.8 7.9 7.6
Preening
1 2 3 4 5 7
1.7 2.2 2.6 2.7 3.4 2.2
.7 1.9 2.4 2.5 2.1 2.4
1.0** .3 .2 .2 1.3** -.2
Moving
1 2 3 4 5 7
1.1 .7 1.1 1.1 .9 1.0
.5 .9 .5 .8 .7 .5
.6** -.2
1 2 3 4 5 7
3.1 3.9 4.3 3.6 4.8 4.4
4.1 4.4 3.3 3.5 3.9 4.7
Pecking inedible objects
1 2 3 4 5 7
.7 .7 .4 .4 .6 .6
.2 .8 1.1 .4 .6 .9
.5** -.1 -.7** 0 0 -.3
Feather pecking
1 2 3 4 5 7
.5 .3 .2 .3 .2 .5
.2 .1 .1 .5 .6 .2
.3* .2 .1 -.2 _ 4**
Crouching
Feeding
Difference 2.0** 2.0** 2.3** 1.1* .5 2.4** -2.9**
-1.6** -4.0** -1.3* -2.2** -2.3**
n **
.3 .2 .5* -1.0* -.5 1.0* .1 .9 -.3
.3*
'Birds were housed four per cage in 30.5 X 45.7-cm (deep) or 45.7 X 30.5-cm (shallow) cages with 7.6 or 11.4 cm feeder space/hen, respectively. *P<.05. **P<01.
Downloaded from http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
Behavior
ADAPTATION OF FLOOR-REARED PULLETS TO CAGES 1U "
b
3 O X (A •o
-a- Deep Cages -•- Shallow Cages
8-
— - 6o
'C d> Q. C
1 A
42 0H 4
'
1
6
•
i
8
i
i
10
i
i
12
.
,
j
14
16
i
i
18
i
i
20
Hours Within the Day FIGURE 2. Diumal pattern of feeding comparing deep vs. shallow cages during the "settling in" period. Birds were housed four per cage in 30.5 x 45.7-cm (deep) or 45.7 x 30.5 (shallow) cages with 7.6 or 11.4 cm feeder space/hen, respectively.
pecking may indicate the point at which the birds became socially adapted to each other as well as to their environments. Comforting activity displayed no significant patterns over the first 7 days (Table 3). Pecking of inedible objects had a pattern over time that seemed to be related to that of feeding. Cage shape x days posthousing interactions were significant for all behaviors analyzed (Table 3). Cage shape x days posthousing means for each behavior are shown in Table 4. Standing and crouching behaviors were the most striking in their day-to-day changes associated with cage shape, but causes of the erratic changes are obscure. Diurnal feeding patterns are shown in Figure 2 for the birds in both deep and shallow cages. Feeding activity was no higher initially after lights were turned on (0600 h) than during most afternoon hours. Feeding was at the lowest level at 1000 h. Differences in diurnal feeding patterns between Experiments 1 and 2 were striking. In Experiment 2, the dark period lasted only 9 h instead of 12 h as in Experiment 1, and birds were fed at approximately 1030 h, causing a significant (P<.05) rise in frequency of feeding activity that peaked at 1200 h. After that peak, feeding activity fluctuated, but appeared to drop off slightly prior to lights out. Underlying patterns were apparently disrupted at feeding time. Hens in shallow cages did not have such extreme fluctuations in feeding patterns. This may have
Downloaded from http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
quent changing of places at the feed trough that must take place for all birds to feed at a rate similar to that of the birds in shallow cages. Frequent shifting of places at the feeder would account for the significantly (P<.05) greater frequency of moving among the hens in deep cages: 1.0 and .6 periods of movement/h in deep and shallow cages, respectively (Table 3). Crouching behavior also may have been affected by activity at the feeder because there was significantly (P<.05) less crouching overall in deep cages than in shallow cages. This may be an indication of fearfulness, caused by the hens in shallow cages being closer to the aisle and the caretakers. Crouching was the predominant activity on Days 1 to 5 and Day 7 posthousing, but the frequency declined throughout the 7-day period. This suggests that if crouching is considered a fear-related activity, such as antipredator behavior (Duncan, 1980), decreases in crouching may be a good indicator of adaptation to a strange environment. Although data in Experiments 1 and 2 are not directly comparable, it is of interest that the incidence of crouching in Experiment 2 was about double that observed in Experiment 1. A possible explanation, consistent with Duncan's hypothesis, is that the difference was due, at least in part, to the fact that caretakers were excluded from the house during the recording photoperiods in Experiment 1, but not during those in Experiment 2. Crouching activity declined in frequency and other activities increased as birds adapted to the new environment in this study. Preening behavior was not significantly affected by cage shape, but the level changed significantly during the days posthousing, with preening activity lowest on Day 1, then gradually increasing in subsequent days (Table 3). This pattern may indicate that preening is an alternate activity to crouching until the time period when other activities normalize. Birds in shallow cages exhibited significantly (P<.05) less movement activity than those in deep cages, perhaps because all could feed simultaneously. Syme (1974) suggested that feather pecking may be a type of social grooming with no injury intent and may be a form of recognition between birds. Feather pecking data in Table 3 show a development pattern supporting the hypothesis of function as a form of recognition: feather pecking was highly variable, when familiarity would have been low, between Days 1 to 3, and then rose and leveled off for both cage shapes on Days 4 through 7. This plateau in feather
77
ANDERSON ET AL.
78
resulted because the feeder area was more accessible in shallow than in deep cages. REFERENCES
Downloaded from http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
Adams, A. W., 1974. Replacing versus not replacing laying hens removal from cages. Poultry Sci. 53:2092-2095. Anderson, K. E., 1987. Effects of type of rearing diet, cage shape, type of cage partition and feed trough partitions on the productivity and behavior of layers. MS Thesis, Kansas State Univ., Manhattan, KS. Anderson, K. E., J. V. Craig, and A. W. Adams, 1985. A methodology for observing and analyzing "settling in" behavior: adaptation of floor-reared White Leghorn pullets to different cage densities. Poultry Sci. 64(Suppl. 1):56. (Abstr.) Banks, E. M., D.G.M. Wood-Gush, B. O. Hughes, and N. J. Mankovich, 1979. Social rank and priority of access to resources in domestic fowl. Behav. Processes 4:197-209. Craig, J. V., 1986. Measuring social behavior: social dominance. J. Anim. Sci. 62:1120-1129. Craig, J. V., A. D. Dayton, V. A. Garwood, and P. C. Lowe, 1982. Selection for egg mass in different social environments. 4. Selection response in Phase I. Poultry Sci. 61:1786-1798. Craig, J. V., and N. C. Ramos, 1986. Competitive feeding behavior and social status in multiple-hen cages. Appl. Anim. Behav. Sci. 16:69-76. Cunningham, D. L., and A. Van Tienhoven, 1984. The effects of management program and social rank on behavior and productivity of White Leghorn layers in cages. Poultry Sci. 63:25-30. Duncan, I.J.H., 1980. The ethogram of the domestic hen. Pages 5-18 in: The Laying Hen and Its Environment. R. Moss, ed. Martinus Nijhoff Publishers, Boston, MA. Duncan, I.J.H., C. J. Savoy, and D.G.M. Wood-Gush,
1978. Observations on the reproductive behavior of domestic fowl in the wild. Appl. Anim. Ethol. 4:2942. Guhl, A. M., 1953. Social behavior of the domestic fowl. Tech. Bull. 73, Kansas Agric. Exp. Stn., Manhattan, KS. Guhl, A. M., 1958. The development of social organization in the domestic chick. Anim. Behav. 6:92-111. Guhl, A. M., and W. C. AUee, 1944. Some measurable effects of social organization in flocks of hens. Physiol. Zool. 17:320-347. Hester, P. Y., and E. K. Wilson, 1986. Performance of White Leghorn hens in response to cage density and the introduction of cage mates. Poultry Sci. 65:20292033. Hughes, B. O., and A. J. Black, 1977. Diurnal patterns of feeding activity in laying hens in relation to dietary restriction and cage shape. Br. Poult. Sci. 18:353-360. Ministry of Agriculture, Fisheries and Food, 1971. Code of recommendations for the welfare of livestock. Code No. 3, Domestic fowls. Ministry of Agriculture, Fisheries and Food, London, UK. Murchison, C., 1936. The time function in the experimental formation of social hierarchies of different sizes in gallus domesticus. J. Soc. Psychol. 7:3-18. Schelderuppe-Ebbe, T., 1922. Beitrage zur Socialpsychologic des Haushuhn, Z. Psychol. 88:225-252. Syme, G. J., 1974. Competitive orders as measures of social dominance. Anim. Behav. 22:931-940. Syme, G. J., L. A. Syme, and D. R. Barnes, 1984. Fowl sociometry: social discrimination and the behavior of domestic hens during food competition. Appl. Anim. Ethol. 11:163-175. United Egg Producers, 1982. Recommended guidelines of husbandry practices for laying chickens. United Egg Producers, Decatur, GA. Williams, C. G., P. B. Siegel, and W. B. Gross, 1977. Social strife in cockerel flocks during the formation of peck rights. Appl. Anim. Ethol. 3:35^5.
1989 Poultry Science 6 8 : 7 0 - 7 8 INTRODUCTION
have shown that deviations from linear hierarchies are common. Guhl (1958) determined that flocks that were assembled immediately after hatching developed a social structure in 8 to 10 wk. Development of a peck order after assembly in floor pens of small flocks of chickens, all of which are strangers, occurs in a period of time when aggression levels are highest. Guhl (1953) and Williams et al. (1977) reported that social interactions for small groups of chickens in floor pens were highest at initial assembly and generally declined and reached a plateau by 10 days postassembly. Their data indicated that the time needed to integrate into a social group was much less than Murchison (1936) originally proposed. Schelderuppe-Ebbe (1922), Guhl and Allee (1944), and Duncan et al. (1978) provided indirect evidence that hens introduced into socially organized flocks had reduced feed consumption, body weight, and general loss of condition until they had been assimilated into the flock. In contrast, Adams (1974) as well as Hester and Wilson (1986) concluded that introduction of hens into a small group of hens will not reduce performance.
The housing of a floor-reared pullet in a multiple-hen layer cage presents a drastic change in environment. During this period of adaptation or "settling-in" stage, pullets have to adapt to the new physical environment of high density cages that usually includes different styles of feeders and waterers, and strange cage mates. Information is limited on the behavior of pullets during the first few days posthousing in cages. Murchison (1936) examined the time function in the establishment of social hierarchies of the domestic fowl and proposed that individuals in pens of 2, 3, 4, 5, and 6 hens would need 15, 19, 22, 26, and 32 wk, respectively, to establish a linear peck order. His proposal that a "linear" hierarchy would develop was contrary to the findings of Schelderuppe-Ebbe (1922), who showed that nonlinear hierarchies were frequent. Other researchers, Guhl (1953), Craig (1986), and Craig and Ramos (1986) also
'Contribution 88-263-J from the Kansas Agricultural Experiment Station.
70
Downloaded from http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
ABSTRACT Two groups of White Leghorn pullets, reared in floor pens, were observed for changes in behavioral traits when housed in cages. Data in Experiment 1 were obtained during Days 1 to 5 posthousing from 40 pullets kept in eight 40.7-cm wide x 45.7-cm deep cages with either four or six birds/cage and in Experiment 2 during Days 1 to 5 and Day 7 posthousing from 24 pullets housed four/cage in three 30.5-cmwide x 45.7-cm deep cages (deep cages), and three 45.7-cm wide x 30.5-cm deep cages (shallow cages). In Experiment 1, pullets housed four/cage spent significantly (P<.05) fewer periods standing and crouching, but more periods preening, feeding, and performing comfort movements, than those housed six/cage. There was a significant group size x days posthousing interaction for standing and drinking. Standing was most frequent in the four-hen cages on Day 1 and then declined, whereas periods of standing increased in six-bird cages. Drinking behaviors were significantly different only on Day 1; six birds per cage had the lowest level. In Experiment 2, pullets in deep cages spent significantly more periods standing and moving and fewer periods crouching. Crouching frequencies declined from Day 1 to Day 7 posthousing for birds in both deep and shallow cages. Although there were significant cage shape x days posthousing interactions for all behavior observed, the interactions appeared to be associated with erratic day-to-day differences between hens in deep and shallow cages. (Key words: cage shape, density, settling in behavior)
ADAPTATION OF FLOOR-REARED PULLETS TO CAGES
MATERIALS AND METHODS
Experiment 1. In the rearing phase, egg type pullets (Craig etal., 1982) of the Y2 experimental strain were wing banded, sexed, and assigned randomly to four rearing pens with approximately 125 chicks each at 1 day of age. Pens were in a curtain-sided, naturally ventilated, brooding-rearing house. Supplemental heat was provided by natural gas-fired brooders. The standard Kansas State University feeding regimen, vaccination, and beak trimming procedures were followed (Anderson, 1987). Birds, hatched on June 17, were reared under naturally decreasing day lengths. Two cage environments were used: 1) four birds/cage with 464 cm2 floor area and 10.2 cm feeder space/pullet, which meets minimum space requirements as established in Great Britain by the Ministry of Agriculture, Fisheries, and Food (1971) and 2) six birds/cage with 310 cm2 floor area and 5.1 cm feeder space/bird, which is consistent with minimum space requirements recommended by United Egg Producers (1982) in the US. A common commercial layer cage was used; hens were placed in cages to meet recommended minimum space requirements per hen. As a result, group size and area per bird were confounded. Cages were adjacent in the row to facilitate simultaneous video recording. All cages were 45.7 cm deep X 40.64 cm wide with a continuous-flow water trough at the back of the cage. Feeder space in six-bird cages was restricted by blocking out 5.1 cm of
feeder space at each end with wooden blocks. Surrounding cages were populated to give an environment similar to that of a commercial layer facility. Video observations of settling-in behaviors were made to determine initial adaptation of pullets to the two environments. Twenty pullets were selected randomly from rearing pens at 146 and another 20 at 153 days of age in a way that ensures that as many as possible of the birds were strangers to each other. Because the pullets were reared on decreasing day lengths and no egg production occurred, the age difference of 7 days was thought to have little effect on the behavior observed. Birds were marked for identification by applying different colors to their back feathers before they were placed in cages. Settling-in behavior was observed during Days 1 through 5 posthousing. Birds had received about 12 h natural light in the broodingrearing house just prior to caging and were exposed to 12 h light/day during video recording. All feeding and care was done during the dark hours and the building was locked during the day to minimize disturbance. Observation equipment included two time-lapse recorders with built-in time-date display and two video cameras. The tapes were viewed using a recorder and large-screen monitor. Behaviors evaluated were: standing (otherwise inactive); crouching (off feet); preening; moving (walking and attempting to run or fly); feeding (pecking movements at feed in the trough); drinking; comfort (movements such as stretching and feather fluffing); pecking inedible objects other than feathers; and feather pecking. Other behaviors were observed, but their incidences were so low that analysis was not appropriate. A scanning technique (Anderson et al., 1985) was used for viewing the tapes. Filming was done using a 12-h mode on the recorder. Viewing was done at six times normal speed (2-h mode), i.e., scans were made every 180 s of actual time, providing 30 s of viewing time. Within this 30-s period, each chicken was observed for approximately 5 s and the behavior seen was recorded. Pullets were viewed in the same order in each scanning period. Tapes were viewed by two trained observers in a random order to avoid any biases. Experiment 2. In the rearing phase, approximately 1,800 day-old chicks of a commercial strain (Hyline W-77) were obtained from a local hatchery. Rearing practices were the same as in Experiment 1 except the chicks were fed either
Downloaded from http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
Schelderuppe-Ebbe (1922) determined that birds work out a social structure in which they discriminate between individuals. Syme et al. (1984) further stated that hens associate to a greater degree with lower or equally ranked birds within the group. This allows the birds to acquire their essential needs without attack or threats from higher ranked individuals. Cunningham and Van Tienhoven (1984) reported that the presence of higher ranking hens decreased egg production of the low ranking birds in multiple-bird cages. This effect was reduced by using shallow instead of deep cages, ad libitum rather than restricted feeding, and more space per hen. The objective of the experiments reported here was to determine the amount of time spent in various behaviors of floor-reared pullets as they settled into cage environments with different cage shapes and numbers of birds per cage.
71
ANDERSON ET AL.
72
RESULTS AND DISCUSSION
Experiment 1. Group size had significant (P< .05) effects on the amount of standing, crouching, preening, feeding, and comfort movements during the first 5 days posthousing in layer cages (Table 1). Hens housed four/cage spent significantly less time standing than hens housed six/ cage. Time spent standing was relatively constant over the first 5 days posthousing with a slight, but significant (P<.05) decrease during Days 2 and 3, followed by a return to the original level by Day 5. Examination of data for group size X days posthousing (Table 2) indicate that hens housed four/cage actually had more standing on Day 1, but reduced frequency of standing thereafter as compared with those housed six/ cage. Crouching, which may be an indication of fearfulness (Duncan et al., 1978), was signifi-
cantly (P< .05) lower with four hens/cage than with six/cage (Table 1). Crouching behavior declined significantly over days posthousing, suggesting that hens became less fearful, which allowed more time for other behaviors. The results indicate that group size does have an effect on development of the bird's initial behavior pattern. Standing and crouching had significantly lower frequencies in the smaller group size. Crouching may be the best single indicator of adaptation, being higher on Day 1 posthousing and then declining throughout the first 4 days. Significantly (P<.05) greater preening of hens housed four per cage (Table 1) suggests that hens housed six per cage may not have had sufficient space to perform grooming freely. Preening tended to increase after the 1st day, which may indicate a lower level of stress on the bird. Feeding activity was significantly more frequent in four-hen cages than in six-hen cages (Table 1). This may have been the result of availability of feeder space to the different hen populations. Hens in the four-bird cages could feed simultaneously, whereas those in the sixhen cages had to compete for access to the feeder. Feeding activity was lowest on Day 1, possibly because of unfamiliarity with the environment. Feeding activity then increased and leveled off over the remaining 4 days. Comfort activity also showed a significant difference associated with group size, with four hens/cage performing more comfort type behaviors than with six/cage. This may have been the result of the increased space per hen in the four-hen cages, which allowed for more activity. Pecking inedible objects increased over Days 1 and 2, then reached a plateau on the remaining days. Means for group size x days posthousing interactions for standing and drinking behaviors are presented in Table 2. Periods of standing of hens in four-bird cages were significantly more frequent on Day 1, then dropped to frequencies lower than those of pullets in six-bird cages on subsequent days. Levels of drinking activity were significantly different for group sizes on Day 1 only, with hens housed four/cage drinking more than those housed six/cage. Diurnal feeding patterns during hours when caretakers were absent were similar for pullets in both four and six-bird cages. Feeding activity levels shown in Figure 1 were highest over the first 4 h after lights were turned on (0600 h), then stayed at a plateau at a lower level over
Downloaded from http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
the standard Kansas State University step-down protein regimen or a step-up protein regimen (Anderson, 1987). At 18 weeks of age, a random sample of 12 pullets from each feeding regimen was housed in three adjacent cages, four birds/ 30.5 X 45.7-cm (deep) or 45.7 X 30.5-cm (shallow) cage located in two center rows of double-deck cages in a curtain-sided, naturally ventilated house. Pullets had 348 cm2 floor area and 7.6 or 11.4 cm feeder space/bird, respectively, in deep and shallow cages. Settling-in behavior was video recorded during Days 1 through 5 and on Day 7 posthousing. Birds had received 15 h supplemental light in the brooding-rearing house just prior to caging and were exposed to 15 h light/day during filming. All feeding was done at 1000 h and egg collection at 1300 h, so that day-to-day comparisons would be comparable in terms of disturbance by humans. Filming was done using the 24-h mode on the recorder. Observation techniques were the same as in Experiment 1 except that viewing was done at 12 times normal speed (2-h mode). Using the scanning technique, a 180-s actual time period was viewed in 15 s. Data were pooled for the birds housed at 146 and 153 days of age and then summarized on an hourly basis for each day posthousing. Data were then subjected to the ANOVA procedure with a split-split-plot design over days posthousing with repeated measures over hours within days. Means for days and hours were tested by least significant differences when significant differences were present.
5.0 a 4.2 b 4.0 b 3.4C 3.4C
5.5 a 4.9 b 4.9 b 5.1ab 5.5 a
1 2 3 4 5
Days posthousing (DPH)
Means within columns with no common superscripts differ significantly (P<.05).
2.8 a 3.1ab 3.5 b c 3.7C 3.3abc
3.9* 2.9
Preening 1.3 1.2 12ab 1.2 ab 12ab 1.4a l.lb
Moving
4.0 a 4.9b 4.9 b 4.7b 4.8b
5.0* 4.5
Feeding
PI = Pecking inedible objects; FP = feather pecking.
**P<.01.
*P<.05.
2
Table values are number of 3-min periods/h behavior was observed per pullet. Each pullet was observed 30 s/3-m 464 cm2 floor area and 10.2 cm feeder space/pullet or six birds/cage, with 310 cm2 floor area and 5.1 cm feeder space/p
1
GX DPH
3.3* 4.5
4.9* 5.4
4 hens 6 hens
Group size (G)
Crouching
Standing
Treatment
Parameter
TABLE 1. Effect of group size and days posthousing on "settling in " behaviors, Ex
om http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
ANDERSON ET AL.
74
10 3
-o- 4 Hens/Cage -•- 6 Hens/Cage
8-
o
I "5S
o 0)
a 4c
i — i —
— i —
8 10 12 14 Hours Within the Day
16
18
FIGURE 1. Diurnal pattern of feeding comparing four vs. six hens/cage during the "settling in" period. Birds were housed four birds/cage with 464 cm2 floor area and 10.2 cm feeder space/pullet or six birds/cage, with 310 cm2 floor area and 5.1 cm feeder space/pullet.
higher level on Days 5 and 7, which seems to indicate adaptation to the environment. In shallow cages feeding activity was greater on Day 2 than on Day 1; however, it dropped at Day 3 and began a slow increase through Day 7. This difference in feeding activity in deep vs. shallow cages may have resulted from less competition at the feeder in shallow cages. Guhl (1953) noted that aggression occurs when birds are competing for resources of feed, water and space. This may have been the reason for changes in feeding
TABLE 2. Treatment means for behaviors in which group size interacted with days posthousing. Experiment
1'
Behavior
Days p o s t h o u s i n g
4 pu Uets/cage
6 pullets/cage
Difference
Standing
1 2 3 4 5
5.9 4.5 4.6 4.6 4.9
5.2 5.2 5.0 5.5 5.9
.7* -.7* -.4 -.9* -1.0*
Drinking
1 2 3 4 5
.6 .7 .7 .7 .8
.4 .7 .6 .7 .8
.2** .0 .1 .0 .0
1 Birds were housed four birds/cage with 464 cm2 floor area and 10.2 cm feeder space/pullet or six birds/ cage, with 310 cm2 floor area and 5.1 cm feeder space/pullet.
*P<.05. **P<.01.
Downloaded from http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
the next 5 h; levels were not significantly different until 1400 h. Feeding periods were fairly constant during the middle of the day, then increased moderately until 1 h prior to lights out (1700 h). Periods of feeding declined sharply during the last hour before darkness. This pattern is similar to that found by Hughes and Black (1977), who reported the same general diurnal pattern of feeding, but without the sharp decline during the last hour. Experiment 2. Cage shape caused significant differences in behavior patterns. Pullets in deep cages spent significantly (P<.05) more frequent periods standing than those in the shallow cages (Table 3) during all six observation days posthousing except Day 5 (Table 4). The overall higher incidence of standing in deep cages may have resulted from greater competition for feeder space in those cages. Hens in shallow cages also spent less time moving. This may have been the result of the greater feeder space allowed per hen in the shallow cage. Birds housed in both deep and shallow cages fed the same number of periods per hour during the settling-in period (Table 3). There were significant cage shape x days posthousing interactions for all behaviors observed (Table 3). Feeding activity was generally greater after Day 1 in deep cages, possibly because of greater fearfulness associated with unfamiliarity with the environment on Day 1. Feeding activity increased the following day, most likely because of increasing hunger. Feeding activity appeared to reach a plateau at a
*
** *
*
*
*
PI = Pecking inedible objects; FP = feather pecking.
***P<.001.
**P<.01.
*P<.05.
2
'Table values are number of 3-min periods/h behavior was observed per pullet. Each pullet was observed 30 s/3-min 45.7-cm (deep) or 45.7 X 30.5-cm (shallow) cages with 7.6 or 11.4 cm feeder space/hen, respectively.
Means within columns with no common superscripts differ significantly (P<.05).
S X DPH
3.8 3.5 4.4 4.6
42
3 6
.8a .8a .8a 1.0 a .8a .8a
1.2 d 2.0 C 2.5ab 2.6a 2.7a 2.3bc
8.9a 8.5a 7.5b 7 2 b c 6.9bc 6.5C
4.1a 3.0 C 3.5bc 4.1ab 3.6abc 3.9ab
1 2 3 4 5 7
D a y p o s t h o u s i n g (DPH)
4.0 4.0
1.0* .6
2.5 2.0
6.4* 8.8
4.5* 2.8
Deep Shallow
Shape (S)
Fee
Moving
Crouching
Standing
Treatment
Parameter
Preening
TABLE 3. Effect of cage shape and days posthoustng on "settling in" behaviors, Ex
om http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
ANDERSON ET AL.
76
activity over time, although little aggression was observed. Recent studies by Banks etal. (1979), Craig and Ramos (1986), and review articles by Syme (1974) and Craig (1986) raise questions about acceptance of such general assumptions.
Standing was more frequent on Day 1 than on Days 2 and 3, but was not significantly different from that on Days 4, 5, and 7 (Table 3). The greater standing activity of the deep-caged birds (Table 4) may have been due to the fre-
TABLE 4. Treatment means for' behaviors in which cage shape interacted with day posthousing, Experiment 2 Cage shape 1 Days posthousing
Deep
Shallow
Standing
1 2 3 4 5 7 1 2 3 4 5 7
5.1 4.0 4.6 4.6 3.9 5.1 7.5 7.7 5.5 6.5 5.7 5.3
3.1 2.0 2.3 3.5 3.4 2.7 10.4 9.3 9.5 7.8 7.9 7.6
Preening
1 2 3 4 5 7
1.7 2.2 2.6 2.7 3.4 2.2
.7 1.9 2.4 2.5 2.1 2.4
1.0** .3 .2 .2 1.3** -.2
Moving
1 2 3 4 5 7
1.1 .7 1.1 1.1 .9 1.0
.5 .9 .5 .8 .7 .5
.6** -.2
1 2 3 4 5 7
3.1 3.9 4.3 3.6 4.8 4.4
4.1 4.4 3.3 3.5 3.9 4.7
Pecking inedible objects
1 2 3 4 5 7
.7 .7 .4 .4 .6 .6
.2 .8 1.1 .4 .6 .9
.5** -.1 -.7** 0 0 -.3
Feather pecking
1 2 3 4 5 7
.5 .3 .2 .3 .2 .5
.2 .1 .1 .5 .6 .2
.3* .2 .1 -.2 _ 4**
Crouching
Feeding
Difference 2.0** 2.0** 2.3** 1.1* .5 2.4** -2.9**
-1.6** -4.0** -1.3* -2.2** -2.3**
n **
.3 .2 .5* -1.0* -.5 1.0* .1 .9 -.3
.3*
'Birds were housed four per cage in 30.5 X 45.7-cm (deep) or 45.7 X 30.5-cm (shallow) cages with 7.6 or 11.4 cm feeder space/hen, respectively. *P<.05. **P<01.
Downloaded from http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
Behavior
ADAPTATION OF FLOOR-REARED PULLETS TO CAGES 1U "
b
3 O X (A •o
-a- Deep Cages -•- Shallow Cages
8-
— - 6o
'C d> Q. C
1 A
42 0H 4
'
1
6
•
i
8
i
i
10
i
i
12
.
,
j
14
16
i
i
18
i
i
20
Hours Within the Day FIGURE 2. Diumal pattern of feeding comparing deep vs. shallow cages during the "settling in" period. Birds were housed four per cage in 30.5 x 45.7-cm (deep) or 45.7 x 30.5 (shallow) cages with 7.6 or 11.4 cm feeder space/hen, respectively.
pecking may indicate the point at which the birds became socially adapted to each other as well as to their environments. Comforting activity displayed no significant patterns over the first 7 days (Table 3). Pecking of inedible objects had a pattern over time that seemed to be related to that of feeding. Cage shape x days posthousing interactions were significant for all behaviors analyzed (Table 3). Cage shape x days posthousing means for each behavior are shown in Table 4. Standing and crouching behaviors were the most striking in their day-to-day changes associated with cage shape, but causes of the erratic changes are obscure. Diurnal feeding patterns are shown in Figure 2 for the birds in both deep and shallow cages. Feeding activity was no higher initially after lights were turned on (0600 h) than during most afternoon hours. Feeding was at the lowest level at 1000 h. Differences in diurnal feeding patterns between Experiments 1 and 2 were striking. In Experiment 2, the dark period lasted only 9 h instead of 12 h as in Experiment 1, and birds were fed at approximately 1030 h, causing a significant (P<.05) rise in frequency of feeding activity that peaked at 1200 h. After that peak, feeding activity fluctuated, but appeared to drop off slightly prior to lights out. Underlying patterns were apparently disrupted at feeding time. Hens in shallow cages did not have such extreme fluctuations in feeding patterns. This may have
Downloaded from http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
quent changing of places at the feed trough that must take place for all birds to feed at a rate similar to that of the birds in shallow cages. Frequent shifting of places at the feeder would account for the significantly (P<.05) greater frequency of moving among the hens in deep cages: 1.0 and .6 periods of movement/h in deep and shallow cages, respectively (Table 3). Crouching behavior also may have been affected by activity at the feeder because there was significantly (P<.05) less crouching overall in deep cages than in shallow cages. This may be an indication of fearfulness, caused by the hens in shallow cages being closer to the aisle and the caretakers. Crouching was the predominant activity on Days 1 to 5 and Day 7 posthousing, but the frequency declined throughout the 7-day period. This suggests that if crouching is considered a fear-related activity, such as antipredator behavior (Duncan, 1980), decreases in crouching may be a good indicator of adaptation to a strange environment. Although data in Experiments 1 and 2 are not directly comparable, it is of interest that the incidence of crouching in Experiment 2 was about double that observed in Experiment 1. A possible explanation, consistent with Duncan's hypothesis, is that the difference was due, at least in part, to the fact that caretakers were excluded from the house during the recording photoperiods in Experiment 1, but not during those in Experiment 2. Crouching activity declined in frequency and other activities increased as birds adapted to the new environment in this study. Preening behavior was not significantly affected by cage shape, but the level changed significantly during the days posthousing, with preening activity lowest on Day 1, then gradually increasing in subsequent days (Table 3). This pattern may indicate that preening is an alternate activity to crouching until the time period when other activities normalize. Birds in shallow cages exhibited significantly (P<.05) less movement activity than those in deep cages, perhaps because all could feed simultaneously. Syme (1974) suggested that feather pecking may be a type of social grooming with no injury intent and may be a form of recognition between birds. Feather pecking data in Table 3 show a development pattern supporting the hypothesis of function as a form of recognition: feather pecking was highly variable, when familiarity would have been low, between Days 1 to 3, and then rose and leveled off for both cage shapes on Days 4 through 7. This plateau in feather
77
ANDERSON ET AL.
78
resulted because the feeder area was more accessible in shallow than in deep cages. REFERENCES
Downloaded from http://ps.oxfordjournals.org/ at University of Ulster at Coleraine on May 22, 2015
Adams, A. W., 1974. Replacing versus not replacing laying hens removal from cages. Poultry Sci. 53:2092-2095. Anderson, K. E., 1987. Effects of type of rearing diet, cage shape, type of cage partition and feed trough partitions on the productivity and behavior of layers. MS Thesis, Kansas State Univ., Manhattan, KS. Anderson, K. E., J. V. Craig, and A. W. Adams, 1985. A methodology for observing and analyzing "settling in" behavior: adaptation of floor-reared White Leghorn pullets to different cage densities. Poultry Sci. 64(Suppl. 1):56. (Abstr.) Banks, E. M., D.G.M. Wood-Gush, B. O. Hughes, and N. J. Mankovich, 1979. Social rank and priority of access to resources in domestic fowl. Behav. Processes 4:197-209. Craig, J. V., 1986. Measuring social behavior: social dominance. J. Anim. Sci. 62:1120-1129. Craig, J. V., A. D. Dayton, V. A. Garwood, and P. C. Lowe, 1982. Selection for egg mass in different social environments. 4. Selection response in Phase I. Poultry Sci. 61:1786-1798. Craig, J. V., and N. C. Ramos, 1986. Competitive feeding behavior and social status in multiple-hen cages. Appl. Anim. Behav. Sci. 16:69-76. Cunningham, D. L., and A. Van Tienhoven, 1984. The effects of management program and social rank on behavior and productivity of White Leghorn layers in cages. Poultry Sci. 63:25-30. Duncan, I.J.H., 1980. The ethogram of the domestic hen. Pages 5-18 in: The Laying Hen and Its Environment. R. Moss, ed. Martinus Nijhoff Publishers, Boston, MA. Duncan, I.J.H., C. J. Savoy, and D.G.M. Wood-Gush,
1978. Observations on the reproductive behavior of domestic fowl in the wild. Appl. Anim. Ethol. 4:2942. Guhl, A. M., 1953. Social behavior of the domestic fowl. Tech. Bull. 73, Kansas Agric. Exp. Stn., Manhattan, KS. Guhl, A. M., 1958. The development of social organization in the domestic chick. Anim. Behav. 6:92-111. Guhl, A. M., and W. C. AUee, 1944. Some measurable effects of social organization in flocks of hens. Physiol. Zool. 17:320-347. Hester, P. Y., and E. K. Wilson, 1986. Performance of White Leghorn hens in response to cage density and the introduction of cage mates. Poultry Sci. 65:20292033. Hughes, B. O., and A. J. Black, 1977. Diurnal patterns of feeding activity in laying hens in relation to dietary restriction and cage shape. Br. Poult. Sci. 18:353-360. Ministry of Agriculture, Fisheries and Food, 1971. Code of recommendations for the welfare of livestock. Code No. 3, Domestic fowls. Ministry of Agriculture, Fisheries and Food, London, UK. Murchison, C., 1936. The time function in the experimental formation of social hierarchies of different sizes in gallus domesticus. J. Soc. Psychol. 7:3-18. Schelderuppe-Ebbe, T., 1922. Beitrage zur Socialpsychologic des Haushuhn, Z. Psychol. 88:225-252. Syme, G. J., 1974. Competitive orders as measures of social dominance. Anim. Behav. 22:931-940. Syme, G. J., L. A. Syme, and D. R. Barnes, 1984. Fowl sociometry: social discrimination and the behavior of domestic hens during food competition. Appl. Anim. Ethol. 11:163-175. United Egg Producers, 1982. Recommended guidelines of husbandry practices for laying chickens. United Egg Producers, Decatur, GA. Williams, C. G., P. B. Siegel, and W. B. Gross, 1977. Social strife in cockerel flocks during the formation of peck rights. Appl. Anim. Ethol. 3:35^5.