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Effects of Cage Design and Bird Density on Layers
Effects of Cage Design and Bird Density on Layers. 1. Productivity, Feathering, and Nervousness1 M. D. OUART 2 and A. W. ADAMS Department of Animal Sciences and Industry, Kansas State University, Manhattan, Kansas 66506 (Received for publication June 22, 1981)
1982 Poultry Science 61:1606-1613 INTRODUCTION
Several workers have reported that layers housed in shallow (wider than deep) cages at high bird densities exhibited superior performance to those in deep (deeper than wide) cages (Bell, 1972, 1977; Lee and Bolton, 1976; Hughes and Black, 1976; Muir, 1976, Muir and Gerry, 1976; Martin, 1977). Hill and Hunt (1978) observed opposite results. Robinson (1979) reported that crowding hens in cages included three factors: 1) increased colony size, 2) decreased floor area, and 3) decreased feeder space. He reported feeder space per bird the most important causative factor for performance differences. Adams et al. (1978) found that caged, egg-type chickens with heavy feather damage were fearful or nervous. Leeson and Morrison (1978) found positive correlations between feed efficiency, feather coat weight, and a subjective feather cover score, indicating that feather cover could affect heat loss in cold stress and be responsible for differences in feed efficiencies. Effects of low bird density on reduction of feather damage and nervousness are well documented, whereas results conflict on the
'Contribution 81-440-j, Department of Animal Sciences and Industry, Agricultural Experiment Station, Kansas State University, Manhattan, KS 66506. 2 College of Agricultural Sciences, Colorado State University, Fort Collins, CO 80523.
effect of cage shape on those two factors (Hughes and Black, 1974, 1976; Hill and Hunt, 1978). Cage design has been implicated as a possible cause of egg damage (Leech and Knowles, 1969; Anderson et al., 1970). The objectives of these experiments were to investigate the effect of cage shape, amount of feeder space per cage, a cage barrier, and bird density on productivity, income over feed cost, feather cover, and nervousness of layers. MATERIALS AND METHODS
Experiment 1. Day-old female chicks of two commercial strains of Single Comb White Leghorns (SCWL) were reared separately on litter in an open-sided house. The chicks were debeaked at 4 weeks of age. Twenty and 18% protein starter and grower rations, respectively, were fed ad libitum from 0 to 8 and 9 to 20 weeks. The birds were exposed to natural daylight from 0 to 16 weeks. At 16 weeks of age they were redebeaked and moved to an 11 X 36.5 m fan-ventilated, windowless, cage layer house where diey were temporarily housed, 16 per cage, in 71 x 81 cm colony cages and given 12 hr of light per day. The pullets were moved into the experimental cages at 22 weeks. The house contained six rows of cages in three back-to-back double rows. Birds were housed in three cage designs (cage shape — feeder space combinations). Floor area per bird was 516 and 387 cm , respectively, for 3 and 4 birds per cage. The summary of treatments is
1606
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ABSTRACT Experiment 1 compared the effects of cage shape, feeder space, and bird density on performance, nervousness, and feathering of two commercial Single Comb White Leghorn (SCWL) strains. Strain 1 birds and those housed 3 per cage produced more eggs with fewer body checks and cracks, tended to be less nervous, and had better feather cover than strain 2 birds and those housed 4 per cage (P<.05). Experiment 2 compared the effects of cage shape, feeder space, cage barrier, and bird density on performance of a commercial SCWL strain. Hens in cages with 3 birds laid at 5.4% higher rate (HH) and produced 2.8% fewer undergrade eggs than hens housed 4 per cage (P<.05). (Key words: cage design, egg production, feathering, nervousness)
10.2 7.6 10.2 7.6 16.9 12.7 16.9 12.7
10.2 7.6 10.2 7.6 16.9 12.7
—
+ +
+
+
-
barrier
Duration of lay periods was 48 and 23 weeks for Experiments 1 and 2, respectively.
3 4 3 4 3 4 3 4
3 4 3 4 3 4
No. of birds/cage
24 cages per treatment.
Barrier of 2.5- X 5.0-cm wire mesh was positioned randomly 5.5 cm left or right of center of cage and extended 10
Deep 30.5 X 50.8 cm ; shallow, 50.8 X 30.5 cm.
5
4
3
2
in)
Feeder space/hen
Diagrams of cage designs are presented in Figure 1.
30.5 30.5 30.5 30.5 50.8 50.8 50.8 50.8
Deep Deep Shallow Shallow Shallow Shallow Shallow Shallow
1
30.5 30.5 30.5 30.5 50.8 50.8
Feeder space/cage
Deep Deep Shallow Shallow Shallow Shallow
Cage shape 3
Experiment l 2
TABLE 1. Cage design (cage shape - feeder space - cage barrier) and bird density treatments used with SC
m http://ps.oxfordjournals.org/ at Columbia University Libraries on November 6, 2014
QUART AND ADAMS
1608
iFeeder 30.5
-
50.8
FIG. 1. Design of cages, Experiment 1.
indicated in Table 1 and diagrams of cage designs in Figure 1. Feeder space was restricted by attaching 2.5 X 5.0 cm wire mesh over 20.3 cm of the cage front. Each cage was equipped with one automatic watering cup. The birds in one cage per treatment per row were weighed at 22 and 71 weeks. During the experiment, the birds received 14 hr of artificial light (0600 to 2000 hr) daily starting at 23 weeks of age. They were fed 17 and 18% layer rations from 23 to 30 and 30 to 72 weeks of age, respectively. Birds that died were replaced during the first 2 weeks posthousing (22 to 2 3 weeks). Records were maintained on egg production and mortality of all birds, feed consumption of hens in one row, and egg quality and egg loss of hens in two rows from 24 to 72 weeks. Numbers __of hard and_ soft shelled eggs broken through cage floors were observed and recorded 3 consecutive days each 28 days. Measurements during the first two observations were made by counting all new broken eggs found in the manure pit each 24 hr then masking them with a dye solution (Miller and Mellor, 1971). The system reported by Roland (1977) for determining uncollectable eggs was used for the next nine observations. Harvestable eggs, gathered from the same rows on the same days as egg loss observations, were candled to determine egg quality (US Department of Agriculture [USDA]., 1975). Feather condition and nervousness of birds were evaluated every 56 days on two backto-back double rows. Estimates of average feather coat damage of birds in each cage were
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Feeder [•
made (Adams et al., 1978). Birds without feather damage on the back and wings were scored 9 and those with essentially bare backs and wings were scored 1; those with some feather damage were scored between 1 and 9. Estimates of the average fear or flightiness of birds in each cage also were made by a modification of Hansen's (1976) scoring procedure. Birds that were calm and showing no nervous or evasive behavior were scored 0 and those showing hysterical episodes were scored 5; those showing some nervous behavior were scored between 1 and 5. The observer stood in front of the cage, raised his arm and hand from his side to level with the top of the cage, lowered it, and recorded the birds' average response. Experiment 2. Day-old female chicks of a commercial strain of SCWL were placed on litter in an open-sided house. All chicks were debeaked at 3 weeks and redebeaked at 22 weeks. They were exposed to a step-up, stepdown lighting program from 4 days through 20 weeks and natural daylight (approximately 15 hr) until transfer to the cages at 22 weeks of age. The feeding program and cage house were the same as in Experiment 1. The birds were housed in four cage designs (cage shape-feeder space-cage barrier combinations). Floor areas per bird and birds per cage were the same as in Experiment 1. A barrier of 2.5 x 5.0 cm wire mesh was positioned in the cage in addition to covering 20.3 cm of the cage front as in Experiment 1, as observations during Experiment 1 suggested that birds' shoulder space was most critical in restricting access to the feeder. Birds that died were replaced. The summary of treatments is given in Table 1 and diagrams of cage design in Figure 2. Egg production and egg loss (by procedures used in the last nine observations of Experiment 1) were measured except egg loss was measured every 14 rather than 28 days. Egg quality was evaluated by gathering and identifying harvestable eggs as in Experiment 1 and classifying them according to USDA standards for individual eggs (USDA, 1975). A fire terminated this study after 23 weeks of lay. Statistical Analysis. Data were analyzed by analysis of variance. Least significant differences were used to test for differences between specific treatments found to be significant by analysis of variance. Income over feed cost was calculated from performance data
CAGE AND PRODUCTIVITY, FEATHERING, AND NERVOUSNESS
T~ 50.8
2
30.5
feeder 30.5
| ~
Feeder -
-
30.5
I
- J 50.8
U
50.8
4
3
Feeder 50.8
-
FIG. 2. Design of cages, E x p e r i m e n t 2.
to show the economic importance of various treatments. RESULTS AND DISCUSSION
Experiment 1. Only bird density and strain significantly (P<.05) affected egg production (Table 2). Decreased population and concomitant increased floor area per bird increased hen-day (3.4%) and hen-housed (3.5%) egg production. Strain 1 birds had significantly better hen-day (3.0%) and hen-housed (3.1%) egg production than strain 2 birds. Confounding cage shape and feeder space in some previous experiments may have resulted in significant differences attributed to cage shape (Bell, 1972, 1977; Lee and Bolton, 1976; Hughes and Black, 1976; Muir and Gerry, 1976; Hill and Hunt, 1978). None of the variables significantly affected mortality, which generally agrees with Lee and Bolton (1976) and Hill and Hunt (1978). Bell (1972) suggested that shallow cages reduced mortality. Increasing feeder space in shallow cages from 30.5 to 50.8 cm significantly (P<.05) increased body weight gain (6.3%), confirming Lee and Bolton's (1976) report that cage shape did not significantly affect weight gain of light-weight layers. None of the variables had a significant effect on feed consumption or feed conversion. Only strain of birds had a significant (P<.05) effect on the percentage of eggs broken through cage floors (Table 3). Strain 1 hens lost fewer eggs than strain 2 hens (2.7 vs. 6.6%) and also produced significantly (P<.05) fewer (2.1%) checked and cracked eggs. Birds housed at the higher density produced a significantly (P<.05)
higher percentage of body checks and cracks (2.6%) than those in lower density cages, confirming Roland's (1978) and Hill and Hunt's (1978) reports that increasing bird density and population size resulted in more cracked eggs. The significant (P<.05) differences between nervous score means (Table 3) suggest that the birds housed 4 birds per cage tended to be more nervous than those in housed 3 birds per cage (1.2 vs. 1.1). Our results agree with Choudary et al. (1972), who reported more flightiness of hens in long narrow-fronted cages than by those in cages more nearly square shaped. Hill and Hunt (1978) found no difference in bird nervousness due to cage shape. Strain 2 birds tended to be more nervous than strain 1 birds (1.3 vs. 1.0). Mean feather scores were not significantly affected by cage shape or amount of feeder space. But the birds housed 3 per cage tended to be better feathered than those 4 per cage (7.4 vs. 7.1). The significant differences between scores for nervousness and feathering due to bird density and strain suggest a statistical basis for a feather damage-nervousness relationship. Such a relationship would support the hypothesis that pain contributes to nervousness of mature layers. Experiment 2. Egg production was significantly affected by bird density (Table 2). The birds housed 3 per cage laid at 77.9 vs. 72.5% for hens 4 per cage, confirming Hill and Hunt's (1978) report that egg production was lower when area per bird was reduced and population size increased. As in Experiment 1, none of the treatments we investigated significantly affected mortality, feed consumption, and feed conversion. Hens housed 4 per cage had significantly (P<.05) more undergrade eggs (2.9%) than hens 3 per cage (Table 3). Cage shape, feeder space, cage barrier, and bird density had no significant effect on egg grade, egg size, or egg loss. Economic Analysis. The means presented for Experiments 1 and 2 show consistent, nonsignificant numerical trends for several of the performance traits studied. The differences may be economically important to egg producers, so they are included in calculations comparing returns over feed cost (Table 4). Confounded comparisons showing the resultant differences when more than one cage design feature was changed are included in the analysis of both experiments for the various factors studied. Egg income, fowl income, feed costs, and return
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U
1609
72.9 a 75.4 a
76.la 72.7 b
75.9 a 72.9 b
Feeder space shallow cage 30.5 cm 50.8 cm
Bird density 3 hens 4 hens
Strain 1 2
76.4 a 77.0 a 77.9 a 72.5°
Cage barrier, shallow cage Barrier No barrier
Bird density 3 hens 4 hens
2
10.4a 6.0a
12.3a 7.6 a
5.7a 12.3a
7.1a 5.7 a
13.6 a 16.4 a
15.0 a 15.0 a
15,4 a 16.2 a
13.4 a 15.4 a
Mortality
Body weight gain = [ (ending body weight - beginning body weight)/ending body weight ] X 100.
Means within a treatment-column cell with different superscripts differ significantly (P<.05).
74.3 a 76.4 a
Feeder space,shallow cage 30.5 cm 50.8 cm
1
73.la 74.3 a
69.0 a 65.9 b
69.2 a 65.7 b
66.0 a 68.4 a
67.9 a 66.0 a
(%)
Hen-housed egg production
Cage shape,30.5 cm feeder space Deep Shallow
Experiment 2
74.8 a ' 72.9 a
Cage shape, 30.5 cm feeder space Deep Shallow
Experiment 1
Hen-day egg production
30.7 a 28.7 a
31. l a 28.3 a
27.6 a 33.9 b
27.6 a 27.6 a
Body weight gain2
TABLE 2. Means for egg production, mortality, body weight gain, feed consumption, and feed con
m http://ps.oxfordjournals.org/ at Columbia University Libraries on November 6, 2014
.8* .7*
Cage barrier, shallow cage Barrier No. barrier 61.6* 57.5*
57.5* 62.5*
55.7* 57.5*
Higher nervous scores (1 to 5) denote higher nervousness.
'Higher feather scores (1 to 9) denote less feather damage.
1
32.4* 32.6*
34.1* 29.8*
35.9* 34.1*
30.2* 35.9*
Grade A, medium
Grade A, large
62.5* 55.7*
1.0* 1.3b
1.1* 1.2b
1.1* 1.3*
1.0* 1.1*
Nervous score 1
4.7* 6.8 b
4.5*^ 7. l b /
5.7* 5.7*
6.0* 5.7*
Body checks and cracks
ab • ' Means within a treatment within a column with different superscripts differ significantly (P<.05).
4 hens
.3* 1.2*
1.1* .8*
Feeder space, shallow cage 30.5 cm 50.8 cm
Bird density 3 hens
.5* 1.1*
Cage shape, 30.5 cm feeder space Deep Shallow
Experiment 2
2.7* 6.6 b
5.3* 4.0*
Bird density 3 hens 4 hens
Strain 1 2
4.2* 4.9*
Feeder space, shallow cage 30.5 cm 50.8 cm
/ (
4.8* 4.2*
Cage shape, 30.5 cm feeder space Deep Shallow
Experiment 1
(%)
Egg loss
TABLE 3. Means for egg loss, egg quality, hen nervousness, and hen feather scores, Ex
m http://ps.oxfordjournals.org/ at Columbia University Libraries on November 6, 2014
3.89 .84
.14
4.59
6.78 1.85
8.36 .27
1.01
.13 3.83
4.71
1.95
8.65 .27 6.97
50.8 cm
.14 3.98 .73
4.57
7.15 1.70
.27
8.58
Deep/ 30.5 cm
.13 3.83 1.01
1.95
8.65 .27 6.97
Shallow/ 50.8 cm
Confounded comparison 2
cost (Experiments
.1 3.8 1.2
2.0
.2 7.0
8.8
3h
1 and 2
The following prices and calculations were used: A. Prices: Feed, 9^/lb; fowl, 8.25^/lb; Grade A, large eggs, - Sl.ltf/dozen; Grade A, medium eggs, - 43.3^/dozen; Grade A, small eggs, - 2 0 .
.14 3.89 .84
4.59
1.85
6 78
8.36 .27
30.5 cm
Feeder space, shallow
analysis of return ($ per ben) overfeed
3
2
Cages without cage barriers.
Comparison includes both a change in the depth X width dimension and a m o u n t of feeder space per cage (Experiment 2, presence or absenc
E. Feed cost: Experiment 1, (daily feed consumption X 336) X 94; Experiment 2, (daily feed consumption X 161) X 94,
D. Fowl income = (71-week b o d y weight per treatment combination X 8.25<0 - % mortality (Experiment 2 used b o d y weight data from E
in Table 3.
C. Assumed percentages (grade/size): Experiment 1, after subtracting b o d y checks and cracks, Grade A, large - 70%; Grade A, medium -
B. Egg income: Experiment 1, { l(to*tal eggs - n u m b e r of b o d y checks and cracks) X (% grade/size -f 12)] X price per doz } + value of u price per dozen.
1
Feed cost Net return
.14 3.98 .73
4.57
xperiment 2 Egg income
Adjusted fowl income
7.15 1.70
.27
8.58
Feed cost Net return
Egg income Fowl income
xperiment 1
Cage shape Shallow Deep
TABLE 4. Economic
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CAGE AND PRODUCTIVITY, FEATHERING, AND NERVOUSNESS
The confounded cage design comparison showed the additive effects of cage shape, feeder space, and cage barrier differences on returns. Hens in shallow cages, with 50.8 cm of feeder space without cage barriers, returned $.28 more net income per hen than those in deep cages with 30.5 cm of feeder space per cage. In both experiments, increased feeder space acconted for most of the increased net returns among the treatments studied. ACKNOWLEDGMENTS
We thank Arthur Dayton and Kenneth Kemp for assistance with the statistical analyses and Keith Van Skike for assistance with data collection.
REFERENCES Adams, A. W., J. V. Craig, and A. L. Bhagwat, 1978. Effects of flock size, age at housing, and mating experience on two strains of egg-type chickens in colony cages. Poultry Sci. 57:48—53. Anderson, G. B„ T. C. Carter, and R. M. Jones, 1970. Some factors affecting the incidence of cracks in hens' egg shells. Br. Poultry Sci. 11:103-116. Bell, D., 1972. Reverse cage demonstrates striking income advantage. Poultry Dig. 31:326—328. Bell, D., 1977. New cage designs offer higher income advantage. Poultry Tribune 83(5): 14, 16. Choudary, M. E., A. W. Adams, and J. V. Craig, 1972. Effects of strain, age of flock assembly and cage arrangement on behavior and productivity of White Leghorn type chickens. Poultry Sci. 51:1943-1950. Hansen, R. S., 1976. Nervousness and hysteria of mature female chickens. Poultry Sci. 55:531—543. Hill, A. T., and J. R. Hunt, 1978. Layer cage depth effects on nervouness, feathering, shell breakage, performance and net egg returns. Poultry Sci. 57:1204-1216. Hughes, B. O., and A. J. Black, 1974. The effect of environmental factors on activity, selected behavior patterns and "fear" of fowls in cages and pens. Br. Poultry Sci. 16:375-380. Hughes, B. O., and A. J. Black, 1976. Battery cage shape: its effect on diurnal feeding pattern, egg shell cracking, and feather pecking. Br. Poultry Sci. 17:327-336. Lee, D.J.W., and W. Bolton, 1976. Battery cage shape: the laying performance of medium-and-light body weight strains of hens. Br. Poultry Sci. 17:321-326. Leech, F. B., and N. R. Knowles, 1969. An investigation on commercial farms of factors thought to contribute to egg cracking. Br. Poultry Sci. 10:139-147. Leeson, S., and W. D. Morrison, 1978. Effect of feather cover on feed efficiency in laying birds. Poultry Sci. 57:1094-1096. Martin, G. A., 1977. Shallow cage design improves profit. Poultry Tribune 83(3): 32. Miller, M. M., and D. B. Mellor, 1971. Eggs that don't get to market. Poultry Dig. 30:276-278. Muir, F. V., 1976. Performance of Red X Rock sex-linked females in reverse and conventional laying cages of varying heights. Poultry Sci. 55:1234-1238. Muir, F. V., and R. W. Gerry, 1976. Reverse cages and restricted feeding can be used to increase profits with brown egg layers. Feedstuffs 48(35): 18—19. Robinson, D., 1979. Effects of cage shape, colony size, floor area and cannibalism preventative measures on layer performance. Br. Poultry Sci. 20:345-356. Roland, D. A., 1977. An efficient method and procedure for determining the incidence of uncollectable eggs. Poultry Sci. 56:1327-1328. Roland, D. A., 1978. Incidence of body checked and misshapen eggs in relation to number of hens per cage and time of oviposition. Poultry Sci. 57: 1705-1709. US Department of Agriculture, 1975. Egg grading manual. Agric. Handbook No. 75. USDA, Washington, DC.
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on November 6, 2014
over feed cost were based on typical Kansas area prices during 1981. In Experiment 1, return over feed cost was affected by cage shape, amount of feeder space per shallow cage, and bird density. Birds in shallow cages returned $.15 more per bird than those in deep cages. Although egg income showed hens in deep cages more productive, their feed costs more than offset that advantage. Higher productivity by birds in shallow cages with 50.8 cm of feeder space per cage returned $1.95 over feed cost compared with $1.85 by those in cages with 30.5 cm of feeder space. Hens housed 3 per cage outperformed those housed 4 per cage with $2.01 vs. $1.66 returns, respectively. The confounded comparison shows additive effects of cage shape and feeder space. Birds in deep cages with 30.5 cm of feeder space per cage returned $1.70 per hen compared with $1.95 per hen by those in shallow cages with 50.8 cm feeder space per cage. The same basic trends were found in Experiment 2 for return over feed cost; shallow cage shape accounted for a $.11 advantage in returns per hen over deep cages. Egg income was almost equal, so higher feed costs ($.09) shown for the deep cages accounted for most of the difference. Amount of feeder space per cage was responsible for a $.17 difference per hen in returns. Birds in shallow cages with 50.8 cm of feeder space per cage generated more egg income ($.28) with less feed cost ($.15) than those in cages with 30.5 cm per cage. A cage barrier in shallow cages reduced income $.10 per hen. Birds housed 3 per cage returned $1.23 compared with $.64 per bird by hens in housed 4 per cage; differences in egg income and feed costs were responsible.
1613
1982 Poultry Science 61:1606-1613 INTRODUCTION
Several workers have reported that layers housed in shallow (wider than deep) cages at high bird densities exhibited superior performance to those in deep (deeper than wide) cages (Bell, 1972, 1977; Lee and Bolton, 1976; Hughes and Black, 1976; Muir, 1976, Muir and Gerry, 1976; Martin, 1977). Hill and Hunt (1978) observed opposite results. Robinson (1979) reported that crowding hens in cages included three factors: 1) increased colony size, 2) decreased floor area, and 3) decreased feeder space. He reported feeder space per bird the most important causative factor for performance differences. Adams et al. (1978) found that caged, egg-type chickens with heavy feather damage were fearful or nervous. Leeson and Morrison (1978) found positive correlations between feed efficiency, feather coat weight, and a subjective feather cover score, indicating that feather cover could affect heat loss in cold stress and be responsible for differences in feed efficiencies. Effects of low bird density on reduction of feather damage and nervousness are well documented, whereas results conflict on the
'Contribution 81-440-j, Department of Animal Sciences and Industry, Agricultural Experiment Station, Kansas State University, Manhattan, KS 66506. 2 College of Agricultural Sciences, Colorado State University, Fort Collins, CO 80523.
effect of cage shape on those two factors (Hughes and Black, 1974, 1976; Hill and Hunt, 1978). Cage design has been implicated as a possible cause of egg damage (Leech and Knowles, 1969; Anderson et al., 1970). The objectives of these experiments were to investigate the effect of cage shape, amount of feeder space per cage, a cage barrier, and bird density on productivity, income over feed cost, feather cover, and nervousness of layers. MATERIALS AND METHODS
Experiment 1. Day-old female chicks of two commercial strains of Single Comb White Leghorns (SCWL) were reared separately on litter in an open-sided house. The chicks were debeaked at 4 weeks of age. Twenty and 18% protein starter and grower rations, respectively, were fed ad libitum from 0 to 8 and 9 to 20 weeks. The birds were exposed to natural daylight from 0 to 16 weeks. At 16 weeks of age they were redebeaked and moved to an 11 X 36.5 m fan-ventilated, windowless, cage layer house where diey were temporarily housed, 16 per cage, in 71 x 81 cm colony cages and given 12 hr of light per day. The pullets were moved into the experimental cages at 22 weeks. The house contained six rows of cages in three back-to-back double rows. Birds were housed in three cage designs (cage shape — feeder space combinations). Floor area per bird was 516 and 387 cm , respectively, for 3 and 4 birds per cage. The summary of treatments is
1606
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on November 6, 2014
ABSTRACT Experiment 1 compared the effects of cage shape, feeder space, and bird density on performance, nervousness, and feathering of two commercial Single Comb White Leghorn (SCWL) strains. Strain 1 birds and those housed 3 per cage produced more eggs with fewer body checks and cracks, tended to be less nervous, and had better feather cover than strain 2 birds and those housed 4 per cage (P<.05). Experiment 2 compared the effects of cage shape, feeder space, cage barrier, and bird density on performance of a commercial SCWL strain. Hens in cages with 3 birds laid at 5.4% higher rate (HH) and produced 2.8% fewer undergrade eggs than hens housed 4 per cage (P<.05). (Key words: cage design, egg production, feathering, nervousness)
10.2 7.6 10.2 7.6 16.9 12.7 16.9 12.7
10.2 7.6 10.2 7.6 16.9 12.7
—
+ +
+
+
-
barrier
Duration of lay periods was 48 and 23 weeks for Experiments 1 and 2, respectively.
3 4 3 4 3 4 3 4
3 4 3 4 3 4
No. of birds/cage
24 cages per treatment.
Barrier of 2.5- X 5.0-cm wire mesh was positioned randomly 5.5 cm left or right of center of cage and extended 10
Deep 30.5 X 50.8 cm ; shallow, 50.8 X 30.5 cm.
5
4
3
2
in)
Feeder space/hen
Diagrams of cage designs are presented in Figure 1.
30.5 30.5 30.5 30.5 50.8 50.8 50.8 50.8
Deep Deep Shallow Shallow Shallow Shallow Shallow Shallow
1
30.5 30.5 30.5 30.5 50.8 50.8
Feeder space/cage
Deep Deep Shallow Shallow Shallow Shallow
Cage shape 3
Experiment l 2
TABLE 1. Cage design (cage shape - feeder space - cage barrier) and bird density treatments used with SC
m http://ps.oxfordjournals.org/ at Columbia University Libraries on November 6, 2014
QUART AND ADAMS
1608
iFeeder 30.5
-
50.8
FIG. 1. Design of cages, Experiment 1.
indicated in Table 1 and diagrams of cage designs in Figure 1. Feeder space was restricted by attaching 2.5 X 5.0 cm wire mesh over 20.3 cm of the cage front. Each cage was equipped with one automatic watering cup. The birds in one cage per treatment per row were weighed at 22 and 71 weeks. During the experiment, the birds received 14 hr of artificial light (0600 to 2000 hr) daily starting at 23 weeks of age. They were fed 17 and 18% layer rations from 23 to 30 and 30 to 72 weeks of age, respectively. Birds that died were replaced during the first 2 weeks posthousing (22 to 2 3 weeks). Records were maintained on egg production and mortality of all birds, feed consumption of hens in one row, and egg quality and egg loss of hens in two rows from 24 to 72 weeks. Numbers __of hard and_ soft shelled eggs broken through cage floors were observed and recorded 3 consecutive days each 28 days. Measurements during the first two observations were made by counting all new broken eggs found in the manure pit each 24 hr then masking them with a dye solution (Miller and Mellor, 1971). The system reported by Roland (1977) for determining uncollectable eggs was used for the next nine observations. Harvestable eggs, gathered from the same rows on the same days as egg loss observations, were candled to determine egg quality (US Department of Agriculture [USDA]., 1975). Feather condition and nervousness of birds were evaluated every 56 days on two backto-back double rows. Estimates of average feather coat damage of birds in each cage were
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on November 6, 2014
Feeder [•
made (Adams et al., 1978). Birds without feather damage on the back and wings were scored 9 and those with essentially bare backs and wings were scored 1; those with some feather damage were scored between 1 and 9. Estimates of the average fear or flightiness of birds in each cage also were made by a modification of Hansen's (1976) scoring procedure. Birds that were calm and showing no nervous or evasive behavior were scored 0 and those showing hysterical episodes were scored 5; those showing some nervous behavior were scored between 1 and 5. The observer stood in front of the cage, raised his arm and hand from his side to level with the top of the cage, lowered it, and recorded the birds' average response. Experiment 2. Day-old female chicks of a commercial strain of SCWL were placed on litter in an open-sided house. All chicks were debeaked at 3 weeks and redebeaked at 22 weeks. They were exposed to a step-up, stepdown lighting program from 4 days through 20 weeks and natural daylight (approximately 15 hr) until transfer to the cages at 22 weeks of age. The feeding program and cage house were the same as in Experiment 1. The birds were housed in four cage designs (cage shape-feeder space-cage barrier combinations). Floor areas per bird and birds per cage were the same as in Experiment 1. A barrier of 2.5 x 5.0 cm wire mesh was positioned in the cage in addition to covering 20.3 cm of the cage front as in Experiment 1, as observations during Experiment 1 suggested that birds' shoulder space was most critical in restricting access to the feeder. Birds that died were replaced. The summary of treatments is given in Table 1 and diagrams of cage design in Figure 2. Egg production and egg loss (by procedures used in the last nine observations of Experiment 1) were measured except egg loss was measured every 14 rather than 28 days. Egg quality was evaluated by gathering and identifying harvestable eggs as in Experiment 1 and classifying them according to USDA standards for individual eggs (USDA, 1975). A fire terminated this study after 23 weeks of lay. Statistical Analysis. Data were analyzed by analysis of variance. Least significant differences were used to test for differences between specific treatments found to be significant by analysis of variance. Income over feed cost was calculated from performance data
CAGE AND PRODUCTIVITY, FEATHERING, AND NERVOUSNESS
T~ 50.8
2
30.5
feeder 30.5
| ~
Feeder -
-
30.5
I
- J 50.8
U
50.8
4
3
Feeder 50.8
-
FIG. 2. Design of cages, E x p e r i m e n t 2.
to show the economic importance of various treatments. RESULTS AND DISCUSSION
Experiment 1. Only bird density and strain significantly (P<.05) affected egg production (Table 2). Decreased population and concomitant increased floor area per bird increased hen-day (3.4%) and hen-housed (3.5%) egg production. Strain 1 birds had significantly better hen-day (3.0%) and hen-housed (3.1%) egg production than strain 2 birds. Confounding cage shape and feeder space in some previous experiments may have resulted in significant differences attributed to cage shape (Bell, 1972, 1977; Lee and Bolton, 1976; Hughes and Black, 1976; Muir and Gerry, 1976; Hill and Hunt, 1978). None of the variables significantly affected mortality, which generally agrees with Lee and Bolton (1976) and Hill and Hunt (1978). Bell (1972) suggested that shallow cages reduced mortality. Increasing feeder space in shallow cages from 30.5 to 50.8 cm significantly (P<.05) increased body weight gain (6.3%), confirming Lee and Bolton's (1976) report that cage shape did not significantly affect weight gain of light-weight layers. None of the variables had a significant effect on feed consumption or feed conversion. Only strain of birds had a significant (P<.05) effect on the percentage of eggs broken through cage floors (Table 3). Strain 1 hens lost fewer eggs than strain 2 hens (2.7 vs. 6.6%) and also produced significantly (P<.05) fewer (2.1%) checked and cracked eggs. Birds housed at the higher density produced a significantly (P<.05)
higher percentage of body checks and cracks (2.6%) than those in lower density cages, confirming Roland's (1978) and Hill and Hunt's (1978) reports that increasing bird density and population size resulted in more cracked eggs. The significant (P<.05) differences between nervous score means (Table 3) suggest that the birds housed 4 birds per cage tended to be more nervous than those in housed 3 birds per cage (1.2 vs. 1.1). Our results agree with Choudary et al. (1972), who reported more flightiness of hens in long narrow-fronted cages than by those in cages more nearly square shaped. Hill and Hunt (1978) found no difference in bird nervousness due to cage shape. Strain 2 birds tended to be more nervous than strain 1 birds (1.3 vs. 1.0). Mean feather scores were not significantly affected by cage shape or amount of feeder space. But the birds housed 3 per cage tended to be better feathered than those 4 per cage (7.4 vs. 7.1). The significant differences between scores for nervousness and feathering due to bird density and strain suggest a statistical basis for a feather damage-nervousness relationship. Such a relationship would support the hypothesis that pain contributes to nervousness of mature layers. Experiment 2. Egg production was significantly affected by bird density (Table 2). The birds housed 3 per cage laid at 77.9 vs. 72.5% for hens 4 per cage, confirming Hill and Hunt's (1978) report that egg production was lower when area per bird was reduced and population size increased. As in Experiment 1, none of the treatments we investigated significantly affected mortality, feed consumption, and feed conversion. Hens housed 4 per cage had significantly (P<.05) more undergrade eggs (2.9%) than hens 3 per cage (Table 3). Cage shape, feeder space, cage barrier, and bird density had no significant effect on egg grade, egg size, or egg loss. Economic Analysis. The means presented for Experiments 1 and 2 show consistent, nonsignificant numerical trends for several of the performance traits studied. The differences may be economically important to egg producers, so they are included in calculations comparing returns over feed cost (Table 4). Confounded comparisons showing the resultant differences when more than one cage design feature was changed are included in the analysis of both experiments for the various factors studied. Egg income, fowl income, feed costs, and return
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U
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72.9 a 75.4 a
76.la 72.7 b
75.9 a 72.9 b
Feeder space shallow cage 30.5 cm 50.8 cm
Bird density 3 hens 4 hens
Strain 1 2
76.4 a 77.0 a 77.9 a 72.5°
Cage barrier, shallow cage Barrier No barrier
Bird density 3 hens 4 hens
2
10.4a 6.0a
12.3a 7.6 a
5.7a 12.3a
7.1a 5.7 a
13.6 a 16.4 a
15.0 a 15.0 a
15,4 a 16.2 a
13.4 a 15.4 a
Mortality
Body weight gain = [ (ending body weight - beginning body weight)/ending body weight ] X 100.
Means within a treatment-column cell with different superscripts differ significantly (P<.05).
74.3 a 76.4 a
Feeder space,shallow cage 30.5 cm 50.8 cm
1
73.la 74.3 a
69.0 a 65.9 b
69.2 a 65.7 b
66.0 a 68.4 a
67.9 a 66.0 a
(%)
Hen-housed egg production
Cage shape,30.5 cm feeder space Deep Shallow
Experiment 2
74.8 a ' 72.9 a
Cage shape, 30.5 cm feeder space Deep Shallow
Experiment 1
Hen-day egg production
30.7 a 28.7 a
31. l a 28.3 a
27.6 a 33.9 b
27.6 a 27.6 a
Body weight gain2
TABLE 2. Means for egg production, mortality, body weight gain, feed consumption, and feed con
m http://ps.oxfordjournals.org/ at Columbia University Libraries on November 6, 2014
.8* .7*
Cage barrier, shallow cage Barrier No. barrier 61.6* 57.5*
57.5* 62.5*
55.7* 57.5*
Higher nervous scores (1 to 5) denote higher nervousness.
'Higher feather scores (1 to 9) denote less feather damage.
1
32.4* 32.6*
34.1* 29.8*
35.9* 34.1*
30.2* 35.9*
Grade A, medium
Grade A, large
62.5* 55.7*
1.0* 1.3b
1.1* 1.2b
1.1* 1.3*
1.0* 1.1*
Nervous score 1
4.7* 6.8 b
4.5*^ 7. l b /
5.7* 5.7*
6.0* 5.7*
Body checks and cracks
ab • ' Means within a treatment within a column with different superscripts differ significantly (P<.05).
4 hens
.3* 1.2*
1.1* .8*
Feeder space, shallow cage 30.5 cm 50.8 cm
Bird density 3 hens
.5* 1.1*
Cage shape, 30.5 cm feeder space Deep Shallow
Experiment 2
2.7* 6.6 b
5.3* 4.0*
Bird density 3 hens 4 hens
Strain 1 2
4.2* 4.9*
Feeder space, shallow cage 30.5 cm 50.8 cm
/ (
4.8* 4.2*
Cage shape, 30.5 cm feeder space Deep Shallow
Experiment 1
(%)
Egg loss
TABLE 3. Means for egg loss, egg quality, hen nervousness, and hen feather scores, Ex
m http://ps.oxfordjournals.org/ at Columbia University Libraries on November 6, 2014
3.89 .84
.14
4.59
6.78 1.85
8.36 .27
1.01
.13 3.83
4.71
1.95
8.65 .27 6.97
50.8 cm
.14 3.98 .73
4.57
7.15 1.70
.27
8.58
Deep/ 30.5 cm
.13 3.83 1.01
1.95
8.65 .27 6.97
Shallow/ 50.8 cm
Confounded comparison 2
cost (Experiments
.1 3.8 1.2
2.0
.2 7.0
8.8
3h
1 and 2
The following prices and calculations were used: A. Prices: Feed, 9^/lb; fowl, 8.25^/lb; Grade A, large eggs, - Sl.ltf/dozen; Grade A, medium eggs, - 43.3^/dozen; Grade A, small eggs, - 2 0 .
.14 3.89 .84
4.59
1.85
6 78
8.36 .27
30.5 cm
Feeder space, shallow
analysis of return ($ per ben) overfeed
3
2
Cages without cage barriers.
Comparison includes both a change in the depth X width dimension and a m o u n t of feeder space per cage (Experiment 2, presence or absenc
E. Feed cost: Experiment 1, (daily feed consumption X 336) X 94; Experiment 2, (daily feed consumption X 161) X 94,
D. Fowl income = (71-week b o d y weight per treatment combination X 8.25<0 - % mortality (Experiment 2 used b o d y weight data from E
in Table 3.
C. Assumed percentages (grade/size): Experiment 1, after subtracting b o d y checks and cracks, Grade A, large - 70%; Grade A, medium -
B. Egg income: Experiment 1, { l(to*tal eggs - n u m b e r of b o d y checks and cracks) X (% grade/size -f 12)] X price per doz } + value of u price per dozen.
1
Feed cost Net return
.14 3.98 .73
4.57
xperiment 2 Egg income
Adjusted fowl income
7.15 1.70
.27
8.58
Feed cost Net return
Egg income Fowl income
xperiment 1
Cage shape Shallow Deep
TABLE 4. Economic
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CAGE AND PRODUCTIVITY, FEATHERING, AND NERVOUSNESS
The confounded cage design comparison showed the additive effects of cage shape, feeder space, and cage barrier differences on returns. Hens in shallow cages, with 50.8 cm of feeder space without cage barriers, returned $.28 more net income per hen than those in deep cages with 30.5 cm of feeder space per cage. In both experiments, increased feeder space acconted for most of the increased net returns among the treatments studied. ACKNOWLEDGMENTS
We thank Arthur Dayton and Kenneth Kemp for assistance with the statistical analyses and Keith Van Skike for assistance with data collection.
REFERENCES Adams, A. W., J. V. Craig, and A. L. Bhagwat, 1978. Effects of flock size, age at housing, and mating experience on two strains of egg-type chickens in colony cages. Poultry Sci. 57:48—53. Anderson, G. B„ T. C. Carter, and R. M. Jones, 1970. Some factors affecting the incidence of cracks in hens' egg shells. Br. Poultry Sci. 11:103-116. Bell, D., 1972. Reverse cage demonstrates striking income advantage. Poultry Dig. 31:326—328. Bell, D., 1977. New cage designs offer higher income advantage. Poultry Tribune 83(5): 14, 16. Choudary, M. E., A. W. Adams, and J. V. Craig, 1972. Effects of strain, age of flock assembly and cage arrangement on behavior and productivity of White Leghorn type chickens. Poultry Sci. 51:1943-1950. Hansen, R. S., 1976. Nervousness and hysteria of mature female chickens. Poultry Sci. 55:531—543. Hill, A. T., and J. R. Hunt, 1978. Layer cage depth effects on nervouness, feathering, shell breakage, performance and net egg returns. Poultry Sci. 57:1204-1216. Hughes, B. O., and A. J. Black, 1974. The effect of environmental factors on activity, selected behavior patterns and "fear" of fowls in cages and pens. Br. Poultry Sci. 16:375-380. Hughes, B. O., and A. J. Black, 1976. Battery cage shape: its effect on diurnal feeding pattern, egg shell cracking, and feather pecking. Br. Poultry Sci. 17:327-336. Lee, D.J.W., and W. Bolton, 1976. Battery cage shape: the laying performance of medium-and-light body weight strains of hens. Br. Poultry Sci. 17:321-326. Leech, F. B., and N. R. Knowles, 1969. An investigation on commercial farms of factors thought to contribute to egg cracking. Br. Poultry Sci. 10:139-147. Leeson, S., and W. D. Morrison, 1978. Effect of feather cover on feed efficiency in laying birds. Poultry Sci. 57:1094-1096. Martin, G. A., 1977. Shallow cage design improves profit. Poultry Tribune 83(3): 32. Miller, M. M., and D. B. Mellor, 1971. Eggs that don't get to market. Poultry Dig. 30:276-278. Muir, F. V., 1976. Performance of Red X Rock sex-linked females in reverse and conventional laying cages of varying heights. Poultry Sci. 55:1234-1238. Muir, F. V., and R. W. Gerry, 1976. Reverse cages and restricted feeding can be used to increase profits with brown egg layers. Feedstuffs 48(35): 18—19. Robinson, D., 1979. Effects of cage shape, colony size, floor area and cannibalism preventative measures on layer performance. Br. Poultry Sci. 20:345-356. Roland, D. A., 1977. An efficient method and procedure for determining the incidence of uncollectable eggs. Poultry Sci. 56:1327-1328. Roland, D. A., 1978. Incidence of body checked and misshapen eggs in relation to number of hens per cage and time of oviposition. Poultry Sci. 57: 1705-1709. US Department of Agriculture, 1975. Egg grading manual. Agric. Handbook No. 75. USDA, Washington, DC.
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on November 6, 2014
over feed cost were based on typical Kansas area prices during 1981. In Experiment 1, return over feed cost was affected by cage shape, amount of feeder space per shallow cage, and bird density. Birds in shallow cages returned $.15 more per bird than those in deep cages. Although egg income showed hens in deep cages more productive, their feed costs more than offset that advantage. Higher productivity by birds in shallow cages with 50.8 cm of feeder space per cage returned $1.95 over feed cost compared with $1.85 by those in cages with 30.5 cm of feeder space. Hens housed 3 per cage outperformed those housed 4 per cage with $2.01 vs. $1.66 returns, respectively. The confounded comparison shows additive effects of cage shape and feeder space. Birds in deep cages with 30.5 cm of feeder space per cage returned $1.70 per hen compared with $1.95 per hen by those in shallow cages with 50.8 cm feeder space per cage. The same basic trends were found in Experiment 2 for return over feed cost; shallow cage shape accounted for a $.11 advantage in returns per hen over deep cages. Egg income was almost equal, so higher feed costs ($.09) shown for the deep cages accounted for most of the difference. Amount of feeder space per cage was responsible for a $.17 difference per hen in returns. Birds in shallow cages with 50.8 cm of feeder space per cage generated more egg income ($.28) with less feed cost ($.15) than those in cages with 30.5 cm per cage. A cage barrier in shallow cages reduced income $.10 per hen. Birds housed 3 per cage returned $1.23 compared with $.64 per bird by hens in housed 4 per cage; differences in egg income and feed costs were responsible.
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