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Incubation Conditions and Hatchability of Turkey Eggs
Incubation Conditions and Hatchability of Turkey Eggs*' T. C. BYERLY, S. K. HAYNES AND S.(JTMARSDEN Bureau of Animal Industry, V. S. Department of Agriculture, Beltsville, Maryland
M
ANUFACTURERS of some forced draft incubators recommend that turkey eggs be removed from the incubator to a separate hatcher at 24 days' incubation. This change involves a drop in incubation temperature from 99^4 to 97°F., cessation of turning, and a change in position from an angle of 45 degrees from horizontal to a horizontal position in which the eggs lie on their sides. The experiments reported herein were undertaken to determine the effects of transfer to the hatcher and to each of the hatcher conditions at 12, IS, 18, 21, 24, and 25 days' incubation, respectively. The effects of hatcher temperatures of 93, 95, 97, 98, 99-J4 and 102°F. were also determined. Egg length was measured prior to incubation so that its relation to hatchability under the various experimental conditions might be determined. Romanoff (1935) reported experiments in which turkey eggs were incubated for three weeks in a forced draft machine, then transferred to a special laboratory incubator for the fourth week and incubated at temperatures ranging from 30.5-41.5°C. (86.9-106.7°F.). He found that eggs incubated at 36-38°C. (96.8-100.4°F.) during the fourth week hatched best and the resulting poults lived and grew to three weeks' posjnatal age better than poults hatched at lower or higher temperatures. Martin and Insko (1935) reported experinients with still-air machines. They found that. 101 °F. at the top of the in-
cubating egg throughout the incubation period was too low while 103.4°F. during the fourth week of incubation was too high for optimal results in still-air machines. References to earlier literature and to experiment station recommendations will be found in the paper of Martin and InskQ. (1935). MATERIALS AND METHODS
Eggs used in the present study were produced by young hens of several varieties* and crosses* mated to unrelated males, at the National Agricultural Research Center, Beltsville, Maryland. Eggs were collected during the months of April-August, 1937, inclusive. Eggs were held for incubation in an egg room maintained at temperature of about 55°F. for 1-14 days; that is, they were set at weekly or bi-weekly intervals. The incubators used were modern, commercial-type forced draft machines with hatchers of the same make. The machines were operated according to the manufacturer's recommendations (temperature, 99^-100°F.; egg position, 45 degrees from horizontal; turning three times daily) except as noted. All eggs were incubated under standard conditions for 12 days, then candled, and infertile eggs and dead embryos removed. All calculations given are based on embryos alive at 12 days' incubation. * Purebred Bronze, White Holland, White Austrian, Black, and Wild; and hybrids of Bronze, White Holland, and Wild.
[253]
Downloaded from http://ps.oxfordjournals.org/ at H.E.C. Bibliotheque Myriam & J. Robert Ouimet on June 14, 2015
(Received for publication December 9, 1937)
The 16 lots which were turned fewer than 24 days showed an average hatchability of 95.7 ± 1.59 percent of that of their respective controls while the 12 lots changed with respect to position or temperature but not with respect to turning showed an average hatchability of 100.1 ± 1.41 percent of that of their respective controls.
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Downloaded from http://ps.oxfordjournals.org/ at H.E.C. Bibliotheque Myriam & J. Robert Ouimet on June 14, 2015
Seven incubations were conducted. The three factors involved in the normal shift from incubator to hatcher were used in a different combination in each incubation, one lot of eggs being shifted from normal to experimental conditions at 12, IS, 18, 21, 24, and 25 days' incubation, respectively. These seven incubations involved one experiment with each of the possible combinations of the three factors studied since the 24-day lot served as control in each experiment. Other lots of eggs were subsequently incubated for 24 days under normal conditions, then divided into a control lot to be hatched at 97°F., and one or more experimental lots to be hatched at other temperatures. DATA Table 1 shows the number of 12-day embryos and percentage hatchability for the first group of seven incubations. Inspection of the data shows that differences due to treatment were relatively small. The averages for the seven incubations show that eggs transferred from normal incubation conditions prior to the twenty-first day of incubation had about 3 percent lower hatchability than the eggs kept under normal incubation conditions for 21 days or longer. Tabulation of the relative hatchabilities of the lots of eggs, changed to experimental conditions at 12, 15, 18, and 21 days as a percentage of the respective 24day (or control) lots and summary with respect to the three factors involved, yields a clearer picture.
ent
T. C. BYERLY AND OTHERS
Effects on
254
INCUBATION CONDITIONS AND HATCHABILITY OF TURKEY EGGS
TABLE 2.—Effects
research (cf. Byerly and Marsden, 1938). Table 2 shows data for eggs incubated for 24 days under normal conditions, then transferred to the separate hatcher and incubated until hatching was completed at
2.2
Z3
2.4 2.S 2-6 EGG LENGTH (INCHES)
27
FIG. 1. Hatchability of eggs turned fewer than 24 days ( ' a n d colid curve) and of those turned 24 days or more during incubation (o and broken curve). The curves are free hand.
the indicated temperatures. Hatchability was higher at all temperatures than that obtained by Romanoff (1935). The relatively high hatchability at subnormal hatching temperatures is remarkable. It should be recalled, however, that Romanoff (1935) found that poults hatched at abnormal temperatures grew slowly and showed high mortality. Spraddle-legged poults occurred rarely except in the lot hatched at 9 8 ^ °F., and its control hatched at 97°F. Obviously, hatching temperature did not cause the spraddle-legged condition in these lots.
of temperature after 24 days' incubation on hatchability of turkey eggs
Temperature
24-day embryos
Hatchability
Temperature
24-day embryos
Hatchability
degrees F .
number
percent of 24 day embryos
degrees F.
number
percent of 24 day embryos
93 95 97
44 83 240
90.9 88.0 91.3
98.5 99.8 102
39 73 81
92.3 93.2 70.4
Downloaded from http://ps.oxfordjournals.org/ at H.E.C. Bibliotheque Myriam & J. Robert Ouimet on June 14, 2015
The difference between these values is 4.4 ± 2 . 1 1 percent and is statistically significant. The 16 lots shifted to lower temperature prior to 24 days' incubation showed an average hatchability of 99.1 ± 1.29 percent of that of their respective controls while the 12 similar lots not shifted to lower temperature showed an average of 95.7 ± 2.00 percent of that of their controls. The difference, 3.4 ± 2.46 percent, is not significant. The 16 lots shifted from setting trays (with eggs at 45 degree angle) to hatching trays (with eggs lying flat) prior to 24 days' incubation showed an average hatchability of 98.3 ± 1 . 2 6 percent of that of their respective controls while the 12 similar lots not so treated showed an average 96.7 ± 2 . 1 5 percent of the hatchability of their controls. The difference between these values, 1.6 ± 2.50 percent, is not significant. Data for eggs turned fewer than 24 days and for eggs turned 24 days or more were segregated according to egg length. The hatchability of these classified as to length is plotted in Figure 1. There was little difference in the hatchability of the shorter unturned eggs and the shorter turned eggs but the turned eggs of medium and greatest length showed higher hatchability than the similar unturned eggs. Since larger eggs are generally longer, the obvious fact that the turned eggs of medium length showed higher hatchability than those of extreme length, is in accord with results of previous
255
256
T. C. BYERLY AND OTHERS
It has been observed in this and other experiments that the number of helpouts is greatly increased at high hatching temperatures. This fact may be of diagnostic value in cases of poor commercial incubation results.
LITERATURE
Byerly, T. C , and S. J. Marsden, 1938. Weight and hatchability of turkey eggs. Poultry Sci. 17. (in press). Martin, J. H., and W. M. Insko, Jr., 1935. The effect of temperature and position in the incubation of turkey eggs. Poultry Sci. 14:152-155. Romanoff, A. L., 1935. Influence of incubation temperature on the hatchability of eggs, postnatal growth and survival of turkeys. Jour. Agri. Science 25 :318-325.
Downloaded from http://ps.oxfordjournals.org/ at H.E.C. Bibliotheque Myriam & J. Robert Ouimet on June 14, 2015
SUMMARY Seven incubations involving 3,087 turkey eggs were made with various combinations of the three pairs of incubation factors, 99%-97°F. incubation temperature, 45 degree angle—horizontal position of egg, turned three times daily—unturned. In each incubation, one lot of eggs was transferred from control incubation conditions to experimental conditions at 12, 15, 18, 21, 24, and 25 days' incubation, respectively. Change in these three factors prior to 21 days' incubation reduced hatchability about 3 percent. The reduction in hatch-
ability was due to the adverse effect of failure to turn the eggs. Temperature and position were of little consequence under the conditions of the experiment. Longer eggs were more adversely affected by lack of turning than shorter eggs. A total of 570 eggs were incubated for the 25-28 days of incubation, inclusive, at 93, 95, 97, 9&y2, 99%, and 102°F. Hatchability was markedly reduced at 102 °F. but was little affected at the other temperatures.
M
ANUFACTURERS of some forced draft incubators recommend that turkey eggs be removed from the incubator to a separate hatcher at 24 days' incubation. This change involves a drop in incubation temperature from 99^4 to 97°F., cessation of turning, and a change in position from an angle of 45 degrees from horizontal to a horizontal position in which the eggs lie on their sides. The experiments reported herein were undertaken to determine the effects of transfer to the hatcher and to each of the hatcher conditions at 12, IS, 18, 21, 24, and 25 days' incubation, respectively. The effects of hatcher temperatures of 93, 95, 97, 98, 99-J4 and 102°F. were also determined. Egg length was measured prior to incubation so that its relation to hatchability under the various experimental conditions might be determined. Romanoff (1935) reported experiments in which turkey eggs were incubated for three weeks in a forced draft machine, then transferred to a special laboratory incubator for the fourth week and incubated at temperatures ranging from 30.5-41.5°C. (86.9-106.7°F.). He found that eggs incubated at 36-38°C. (96.8-100.4°F.) during the fourth week hatched best and the resulting poults lived and grew to three weeks' posjnatal age better than poults hatched at lower or higher temperatures. Martin and Insko (1935) reported experinients with still-air machines. They found that. 101 °F. at the top of the in-
cubating egg throughout the incubation period was too low while 103.4°F. during the fourth week of incubation was too high for optimal results in still-air machines. References to earlier literature and to experiment station recommendations will be found in the paper of Martin and InskQ. (1935). MATERIALS AND METHODS
Eggs used in the present study were produced by young hens of several varieties* and crosses* mated to unrelated males, at the National Agricultural Research Center, Beltsville, Maryland. Eggs were collected during the months of April-August, 1937, inclusive. Eggs were held for incubation in an egg room maintained at temperature of about 55°F. for 1-14 days; that is, they were set at weekly or bi-weekly intervals. The incubators used were modern, commercial-type forced draft machines with hatchers of the same make. The machines were operated according to the manufacturer's recommendations (temperature, 99^-100°F.; egg position, 45 degrees from horizontal; turning three times daily) except as noted. All eggs were incubated under standard conditions for 12 days, then candled, and infertile eggs and dead embryos removed. All calculations given are based on embryos alive at 12 days' incubation. * Purebred Bronze, White Holland, White Austrian, Black, and Wild; and hybrids of Bronze, White Holland, and Wild.
[253]
Downloaded from http://ps.oxfordjournals.org/ at H.E.C. Bibliotheque Myriam & J. Robert Ouimet on June 14, 2015
(Received for publication December 9, 1937)
The 16 lots which were turned fewer than 24 days showed an average hatchability of 95.7 ± 1.59 percent of that of their respective controls while the 12 lots changed with respect to position or temperature but not with respect to turning showed an average hatchability of 100.1 ± 1.41 percent of that of their respective controls.
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Downloaded from http://ps.oxfordjournals.org/ at H.E.C. Bibliotheque Myriam & J. Robert Ouimet on June 14, 2015
Seven incubations were conducted. The three factors involved in the normal shift from incubator to hatcher were used in a different combination in each incubation, one lot of eggs being shifted from normal to experimental conditions at 12, IS, 18, 21, 24, and 25 days' incubation, respectively. These seven incubations involved one experiment with each of the possible combinations of the three factors studied since the 24-day lot served as control in each experiment. Other lots of eggs were subsequently incubated for 24 days under normal conditions, then divided into a control lot to be hatched at 97°F., and one or more experimental lots to be hatched at other temperatures. DATA Table 1 shows the number of 12-day embryos and percentage hatchability for the first group of seven incubations. Inspection of the data shows that differences due to treatment were relatively small. The averages for the seven incubations show that eggs transferred from normal incubation conditions prior to the twenty-first day of incubation had about 3 percent lower hatchability than the eggs kept under normal incubation conditions for 21 days or longer. Tabulation of the relative hatchabilities of the lots of eggs, changed to experimental conditions at 12, 15, 18, and 21 days as a percentage of the respective 24day (or control) lots and summary with respect to the three factors involved, yields a clearer picture.
ent
T. C. BYERLY AND OTHERS
Effects on
254
INCUBATION CONDITIONS AND HATCHABILITY OF TURKEY EGGS
TABLE 2.—Effects
research (cf. Byerly and Marsden, 1938). Table 2 shows data for eggs incubated for 24 days under normal conditions, then transferred to the separate hatcher and incubated until hatching was completed at
2.2
Z3
2.4 2.S 2-6 EGG LENGTH (INCHES)
27
FIG. 1. Hatchability of eggs turned fewer than 24 days ( ' a n d colid curve) and of those turned 24 days or more during incubation (o and broken curve). The curves are free hand.
the indicated temperatures. Hatchability was higher at all temperatures than that obtained by Romanoff (1935). The relatively high hatchability at subnormal hatching temperatures is remarkable. It should be recalled, however, that Romanoff (1935) found that poults hatched at abnormal temperatures grew slowly and showed high mortality. Spraddle-legged poults occurred rarely except in the lot hatched at 9 8 ^ °F., and its control hatched at 97°F. Obviously, hatching temperature did not cause the spraddle-legged condition in these lots.
of temperature after 24 days' incubation on hatchability of turkey eggs
Temperature
24-day embryos
Hatchability
Temperature
24-day embryos
Hatchability
degrees F .
number
percent of 24 day embryos
degrees F.
number
percent of 24 day embryos
93 95 97
44 83 240
90.9 88.0 91.3
98.5 99.8 102
39 73 81
92.3 93.2 70.4
Downloaded from http://ps.oxfordjournals.org/ at H.E.C. Bibliotheque Myriam & J. Robert Ouimet on June 14, 2015
The difference between these values is 4.4 ± 2 . 1 1 percent and is statistically significant. The 16 lots shifted to lower temperature prior to 24 days' incubation showed an average hatchability of 99.1 ± 1.29 percent of that of their respective controls while the 12 similar lots not shifted to lower temperature showed an average of 95.7 ± 2.00 percent of that of their controls. The difference, 3.4 ± 2.46 percent, is not significant. The 16 lots shifted from setting trays (with eggs at 45 degree angle) to hatching trays (with eggs lying flat) prior to 24 days' incubation showed an average hatchability of 98.3 ± 1 . 2 6 percent of that of their respective controls while the 12 similar lots not so treated showed an average 96.7 ± 2 . 1 5 percent of the hatchability of their controls. The difference between these values, 1.6 ± 2.50 percent, is not significant. Data for eggs turned fewer than 24 days and for eggs turned 24 days or more were segregated according to egg length. The hatchability of these classified as to length is plotted in Figure 1. There was little difference in the hatchability of the shorter unturned eggs and the shorter turned eggs but the turned eggs of medium and greatest length showed higher hatchability than the similar unturned eggs. Since larger eggs are generally longer, the obvious fact that the turned eggs of medium length showed higher hatchability than those of extreme length, is in accord with results of previous
255
256
T. C. BYERLY AND OTHERS
It has been observed in this and other experiments that the number of helpouts is greatly increased at high hatching temperatures. This fact may be of diagnostic value in cases of poor commercial incubation results.
LITERATURE
Byerly, T. C , and S. J. Marsden, 1938. Weight and hatchability of turkey eggs. Poultry Sci. 17. (in press). Martin, J. H., and W. M. Insko, Jr., 1935. The effect of temperature and position in the incubation of turkey eggs. Poultry Sci. 14:152-155. Romanoff, A. L., 1935. Influence of incubation temperature on the hatchability of eggs, postnatal growth and survival of turkeys. Jour. Agri. Science 25 :318-325.
Downloaded from http://ps.oxfordjournals.org/ at H.E.C. Bibliotheque Myriam & J. Robert Ouimet on June 14, 2015
SUMMARY Seven incubations involving 3,087 turkey eggs were made with various combinations of the three pairs of incubation factors, 99%-97°F. incubation temperature, 45 degree angle—horizontal position of egg, turned three times daily—unturned. In each incubation, one lot of eggs was transferred from control incubation conditions to experimental conditions at 12, 15, 18, 21, 24, and 25 days' incubation, respectively. Change in these three factors prior to 21 days' incubation reduced hatchability about 3 percent. The reduction in hatch-
ability was due to the adverse effect of failure to turn the eggs. Temperature and position were of little consequence under the conditions of the experiment. Longer eggs were more adversely affected by lack of turning than shorter eggs. A total of 570 eggs were incubated for the 25-28 days of incubation, inclusive, at 93, 95, 97, 9&y2, 99%, and 102°F. Hatchability was markedly reduced at 102 °F. but was little affected at the other temperatures.