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A Preliminary Study on the Hatchability of Chicken Eggs Subjected to Shaking Agitation1
A Preliminary Study on the Hatchability of Chicken Eggs Subjected to Shaking Agitation 1 CARL A. RANDLES, JR. 2 AND ALEXIS L. ROMANOFF
Agricultural Experiment Station, Cornell University, Ithaca, New York (Received for publication July 29, 1953)
P
IVOTAL displacement or "turning" is a purely physical factor, necessary during incubation for the normal development and hatchability of all domestic fowl embryos. In order to provide the required stimulus, modern commercial incubators are so constructed that the trays of eggs can be tilted back and forth through a 90 degree arc (i.e., 45 degrees each way from horizontal). It is common procedure to candle the eggs and transfer them to hatching trays on the 18th day. If shaking agitation could be substituted for conventional turning, several advantages would ensue: (1) eggs could be incubated and hatched in the same tray; (2) labor costs resulting from the 18-day handling would be eliminated; and (3) incubator space could be utilized more efficiently. There are, however, several experimental observations recorded in the literature which counsel against the workability of such a scheme. Stiles and Watterson (1937) described in rather complete detail the effects of jarring on developing embryos. A 490 gm. weight was dropped a distance of 6 cm. onto a table top upon which the incubator rested. The shocks were delivered at the rate of 15 blows per minute at 15 minute intervals. Only one chick was hatched from 155 eggs so treated. Examination of "jarred" embryos revealed that the vitelline circula1 This work was supported in part by a W. D. James Fellowship. 2 Research Fellow in Chemical Embryology. Present address: 3721 Hard Rd., Worthington, Ohio.
tion and the central nervous system were most seriously affected. Olsen and Byerly (1938) subjected developing eggs of consecutive ages to agitation in a shaking machine. The eggs were displaced over an amplitude of 3 inches at the rate of 229 oscillations per minute for 7 minutes. Eggs shaken parallel to their short axes were more susceptible to damage (ruptured yolks and hemorrhages) than were those shaken parallel to their long axes. The effect of pre-incubation shaking agitation has been studied by Seek (1939) and Landauer and Baumann (1943). The former author concluded that shaking did not have an adverse effect on hatchability when the vitelline membrane was not ruptured. His experimental eggs were displaced a distance of 8 cm. at the rate of 150 excursions per minute for one hour. Landauer and Baumann observed an increased incidence of rumplessness and other abnormalities among chicks and dead-in-shell embryos from shaken eggs. According to their Table 2, the hatchability of shaken eggs was proximately 30 percent and that of control eggs was 67 percent. The duration of shaking was one, two, and three hours. One of the shaking machines used gave a displacement of 5.7 cm.; the other lifted and then dropped the eggs through 3.1 cm. The frequencies were, respectively, 216 and 120 oscillations per minute. In spite of the above indications, it seemed possible that a suitable combination of the shaking variables might be
374
AGITATION OF EGGS AND HATCHABILITY
found which would provide the stimulus of turning. The recognized variables were: (1) frequency, or oscillations per unit of time, (2) duration of shaking period, (3) amplitude of displacement, and (4) interval between shaking periods. The data presented here were collected during a preliminary survey of the problem. EXPERIMENTAL
A standard commercial incubator was fitted with a special mechanism to provide four trays with different shaking frequencies. In the first series of experiments these rates were 121, 173, 197, and 230 oscillations per minute. Later, the rates were changed to 115, 216, 345, and 431 oscillations per minute. In all cases, the amplitude of movement was one-half inch (1.27 cm.). The duration of the shaking period as well as the time interval between periods were adjustable by a time-clock. The same cabinet also contained three trays which provided standard turning conditions (every two hours). The incubation temperature was maintained between 99.5° and 100.0°F. (an average reading would be nearer 100.0°F.). The relative humidity of the air in the cabinet was regulated at about 65 percent. All of the eggs for the experimental tests were obtained from a local commercial breeder-hatchery. They weighed 22 to 23 ounces per dozen, and were individually selected against shell defects and anomalous shapes. The various test groups were constituted by random assortment of all eggs. The first trial (A), with the shaking mechanism was inconclusive. It was found that upon loading the trays with eggs the driving belt developed slippage. Also, the shaken eggs were held in fixed position by wire frames which prevented their moving in the tray as it shuttled.
375
Two groups of shaken eggs hatched 18.5 and 32.0 percent; this was comparable to unturned eggs which hatched 30.6 and 25.7 percent. In the second trial (B), the shaken eggs were free in the bottom of the trays which permitted some movement while being shaken. One group of eggs was shaken at the rate of 121 oscillations per minute, another was shaken at 230 oscillations per minute. In spite of corrective measures, the loaded shaking mechanism would slip when on a dead center. Therefore, the shaken trays were made to agitate at least three times a day by hand-tripping the time clock. The duration of shaking was quite short. The control eggs hatched 90.5 percent while the shaken groups hatched 52.0 and 71.0 percent respectively. The observed 71.0 percent hatchability of those eggs shaken 230 oscillations per minute was evidenced that there is some merit in this method of agitation. In trial C, the shaken eggs were agitated for one minute every two hours and the result was 100 percent mortality among those shaken at 230 oscillations per minute. Only seven eggs survived the 19th day. The hatchability at 121 oscillations per minute was 39.0 percent as compared with 87.0 percent hatchability of the controls. It was evident that a duration of one minute was too severe. In trial D, the duration of shaking was shortened to about 5 to 6 seconds. The hatchability of control eggs was 90.0 percent; the shaken eggs hatched 45.0 percent at 121 oscillations per minute and 49.0 percent at 230 oscillations per minute. After inspection of the results of these first four tests, it could be concluded that too long duration of shaking would kill the embryos in eggs subjected to the higher (230 oscillations/min.) frequency. On the other hand, eggs shaken at the
376
C. A. RANDLES, J R . AND A. L. ROMANOFF
TABLE 1.—Effect of rates of shaking on the hatchabiltiy of chicken eggs {Duration, 2-3 seconds every 2 hours)
near 216, it was decided to try to explore further the effects of duration of shaking. For the succeeding three trials (G, H, Number Number InHatchI), a time-clock was installed which perTreatment of of fertile ability* eggs chicks mitted more exact regulation of the duraControl, turned every tion of shaking between 0.5 second and 2 hours 118 4 106 93.0 Unturned 120 2 47 39.8 13.5 seconds. At the same time, the inter115 oscillations per val between agitations was reduced from minute 118 7 71 64.0 216 oscillations per two hours to one hour; this change was minute 117 1 84 72.4 345 oscillations per inadvertently incorporated into the new minute 118 ? 0 0.0 431 oscillations per timing mechanism. The eggs in trial G minute 118 ? 0 0.0 were shaken for 1.0 second; those in H for * Hatchability of eggs is expressed as percent of fertile eggs. 0.5 second; and those in I for 1.5 seconds. high frequency hatched better than those These data are presented in Table 2. at low frequency when duration was in An unexplainable occurrence in trial G the range of a few seconds. In order to was the poor hatchability (70.0 percent) check hatchabilities at frequencies higher of the control eggs. When agitation of than 230 oscillations/min., the mechanism very short duration (0.5 sec.) was used in was modified so as to provide shaking at trial H, some of the eggs shaken at 345 115, 216, 345, and 431 oscillations/min. oscillations/min. did hatch. But from the Trials E and F were repetitions of the variability of hatchabilities at 115 and 216 same experimental conditions. Groups of oscillations/min., and from the results of eggs were shaken at each of the above fre- previous trials, it would seem that duraquencies and a group of unturned eggs tion of shaking, in the range of a few secwere included in the tests. The duration of onds, is not a critical factor. shaking was 2 to 3 seconds (the slowest DISCUSSION tray made 6 to 8 excursions). The experiThat these results have been different mental value of these trials was quite good since all the known factors and incuba- from earlier studies of shaking agitation tion conditions operated according to is undoubtedly due to the less severe plan. A complete summary of the results treatment given. It is readily apparent, obtained is given in Table 1. from the above data, that the hatchaIt is noteworthy that the control eggs 2.—Effect of rates of shaking and duration o hatched 93.0 percent; the hatchability of TABLE agitation on the hatchability of chicken eggs (Interval, 1 hour) the 115 and 216 oscillations/min. groups was quite good while 345 and 431 oscillaHatchability* tions/min. proved to be completely fatal. Trial G Trial H Trial I The infertility in the 216 group was very Treatment Duration low. These results suggest that an opti1.0 1.5 0.5 mum frequency exists between 115 and second second seconds 345 oscillations/min.; this optimal fre- Control, turned every 2 hours 69.7 89.6 93.1 Unturned 41.8 48.3 44.7 quency is proximate to 216 oscillations 115 oscillations per minute 59.7 63.2 56.5 /min. 216 oscillations per minute 81.8 63.5 63.3 4.5 345 oscillations per minute 1.6 Rather than to become involved in 431 oscillations per minute modification costs that would be incurred * Hatchability of eggs is expressed as percent of fertile eggs. lot contained from 58 to 70 eggs with fertility not less by examination of the many frequencies thanEach 90 percent.
GEORGIA NOTES
bility of shaken eggs can be made significantly better than unturned eggs provided suitable amplitude, frequency, duration, and interval of shaking are used. The average hatchability of 761 unturned eggs was 33.6 percent, while the average hatchability of 1,214 shaken eggs (including all but totally fatal conditions) was 58.7 percent. It would seem then that shaking agitation does provide the physical stimulus for normal development that is derived from "turning." Especial consideration should be given to the increased hatchability which resulted when the shaken eggs were permitted to be free in the bottoms of the shaking trays. This development introduced another variable into the problem. It was observed that shaken eggs would bunch or clump in the center of the trays. The orientation of the eggs was not uniform, and it seemed that those in the midst of the group did not move as freely as those on the periphery. This situation could be obviated by parallel, shallow, crescentic grooves in the tray bottom at right angles to the direction of movement. The eggs would then be oriented with their long axes perpendicular to the direction of motion. The net result would be that the rows of eggs would roll back and forth in the grooves as the tray shuttled. No attempt was made, during these studies, to observe whether developmental anomalies were produced by the treatment. If such were so, it was not ob-
377
vious among the experimental chicks. The only noticeable characteristic of the chicks from shaken eggs was varying degrees of sticky down which condition is very common among chicks from unturned eggs. SUMMARY The hatchability of chicken eggs subjected to shaking agitation was significantly better than unturned eggs, but not as good as normal control eggs. The average hatchability of 1,214 shaken eggs was 58.7 percent of fertile while that of 761 unturned eggs was 33.0 percent. Normal control eggs hatched 90.5 percent of fertile. The best hatchabilities obtained with shaking agitation were 79.0 percent and 82.0 percent (216 oscillations per minute, 1 to 3 seconds). A suggestion was made by which orientation and movement of shaken eggs could be better controlled. REFERENCES Landauer, W., and L. Baumann, 1943. Rumpless. ness of chicken embryos produced by mechanical shaking of eggs prior to incubation. J. ExptlZool. 93: 51-74. Olsen, M. W., and T. C. Byerly, 1938. Resistance of chicken embryos to mechanical disturbances. J. Agr. Res. 56: 221-226. Seek, P., 1939. Der Einfluss heftiger Erschutterungen auf die Brutfahigkeit des Huhnereies. Arch. f. Geflugelkunde 13: 362-367. Stiles, K. A., and R. L. Watterson, 1937. The effect of jarring upon the embryogeny of chick embryos. Anat. Rec. 70: 7-12.
GEORGIA NOTES A poultry testing station is to be erected at the University of Georgia, Athens. It will be a coopera-
tive project between 13 state experiment stations in the southern region.
Agricultural Experiment Station, Cornell University, Ithaca, New York (Received for publication July 29, 1953)
P
IVOTAL displacement or "turning" is a purely physical factor, necessary during incubation for the normal development and hatchability of all domestic fowl embryos. In order to provide the required stimulus, modern commercial incubators are so constructed that the trays of eggs can be tilted back and forth through a 90 degree arc (i.e., 45 degrees each way from horizontal). It is common procedure to candle the eggs and transfer them to hatching trays on the 18th day. If shaking agitation could be substituted for conventional turning, several advantages would ensue: (1) eggs could be incubated and hatched in the same tray; (2) labor costs resulting from the 18-day handling would be eliminated; and (3) incubator space could be utilized more efficiently. There are, however, several experimental observations recorded in the literature which counsel against the workability of such a scheme. Stiles and Watterson (1937) described in rather complete detail the effects of jarring on developing embryos. A 490 gm. weight was dropped a distance of 6 cm. onto a table top upon which the incubator rested. The shocks were delivered at the rate of 15 blows per minute at 15 minute intervals. Only one chick was hatched from 155 eggs so treated. Examination of "jarred" embryos revealed that the vitelline circula1 This work was supported in part by a W. D. James Fellowship. 2 Research Fellow in Chemical Embryology. Present address: 3721 Hard Rd., Worthington, Ohio.
tion and the central nervous system were most seriously affected. Olsen and Byerly (1938) subjected developing eggs of consecutive ages to agitation in a shaking machine. The eggs were displaced over an amplitude of 3 inches at the rate of 229 oscillations per minute for 7 minutes. Eggs shaken parallel to their short axes were more susceptible to damage (ruptured yolks and hemorrhages) than were those shaken parallel to their long axes. The effect of pre-incubation shaking agitation has been studied by Seek (1939) and Landauer and Baumann (1943). The former author concluded that shaking did not have an adverse effect on hatchability when the vitelline membrane was not ruptured. His experimental eggs were displaced a distance of 8 cm. at the rate of 150 excursions per minute for one hour. Landauer and Baumann observed an increased incidence of rumplessness and other abnormalities among chicks and dead-in-shell embryos from shaken eggs. According to their Table 2, the hatchability of shaken eggs was proximately 30 percent and that of control eggs was 67 percent. The duration of shaking was one, two, and three hours. One of the shaking machines used gave a displacement of 5.7 cm.; the other lifted and then dropped the eggs through 3.1 cm. The frequencies were, respectively, 216 and 120 oscillations per minute. In spite of the above indications, it seemed possible that a suitable combination of the shaking variables might be
374
AGITATION OF EGGS AND HATCHABILITY
found which would provide the stimulus of turning. The recognized variables were: (1) frequency, or oscillations per unit of time, (2) duration of shaking period, (3) amplitude of displacement, and (4) interval between shaking periods. The data presented here were collected during a preliminary survey of the problem. EXPERIMENTAL
A standard commercial incubator was fitted with a special mechanism to provide four trays with different shaking frequencies. In the first series of experiments these rates were 121, 173, 197, and 230 oscillations per minute. Later, the rates were changed to 115, 216, 345, and 431 oscillations per minute. In all cases, the amplitude of movement was one-half inch (1.27 cm.). The duration of the shaking period as well as the time interval between periods were adjustable by a time-clock. The same cabinet also contained three trays which provided standard turning conditions (every two hours). The incubation temperature was maintained between 99.5° and 100.0°F. (an average reading would be nearer 100.0°F.). The relative humidity of the air in the cabinet was regulated at about 65 percent. All of the eggs for the experimental tests were obtained from a local commercial breeder-hatchery. They weighed 22 to 23 ounces per dozen, and were individually selected against shell defects and anomalous shapes. The various test groups were constituted by random assortment of all eggs. The first trial (A), with the shaking mechanism was inconclusive. It was found that upon loading the trays with eggs the driving belt developed slippage. Also, the shaken eggs were held in fixed position by wire frames which prevented their moving in the tray as it shuttled.
375
Two groups of shaken eggs hatched 18.5 and 32.0 percent; this was comparable to unturned eggs which hatched 30.6 and 25.7 percent. In the second trial (B), the shaken eggs were free in the bottom of the trays which permitted some movement while being shaken. One group of eggs was shaken at the rate of 121 oscillations per minute, another was shaken at 230 oscillations per minute. In spite of corrective measures, the loaded shaking mechanism would slip when on a dead center. Therefore, the shaken trays were made to agitate at least three times a day by hand-tripping the time clock. The duration of shaking was quite short. The control eggs hatched 90.5 percent while the shaken groups hatched 52.0 and 71.0 percent respectively. The observed 71.0 percent hatchability of those eggs shaken 230 oscillations per minute was evidenced that there is some merit in this method of agitation. In trial C, the shaken eggs were agitated for one minute every two hours and the result was 100 percent mortality among those shaken at 230 oscillations per minute. Only seven eggs survived the 19th day. The hatchability at 121 oscillations per minute was 39.0 percent as compared with 87.0 percent hatchability of the controls. It was evident that a duration of one minute was too severe. In trial D, the duration of shaking was shortened to about 5 to 6 seconds. The hatchability of control eggs was 90.0 percent; the shaken eggs hatched 45.0 percent at 121 oscillations per minute and 49.0 percent at 230 oscillations per minute. After inspection of the results of these first four tests, it could be concluded that too long duration of shaking would kill the embryos in eggs subjected to the higher (230 oscillations/min.) frequency. On the other hand, eggs shaken at the
376
C. A. RANDLES, J R . AND A. L. ROMANOFF
TABLE 1.—Effect of rates of shaking on the hatchabiltiy of chicken eggs {Duration, 2-3 seconds every 2 hours)
near 216, it was decided to try to explore further the effects of duration of shaking. For the succeeding three trials (G, H, Number Number InHatchI), a time-clock was installed which perTreatment of of fertile ability* eggs chicks mitted more exact regulation of the duraControl, turned every tion of shaking between 0.5 second and 2 hours 118 4 106 93.0 Unturned 120 2 47 39.8 13.5 seconds. At the same time, the inter115 oscillations per val between agitations was reduced from minute 118 7 71 64.0 216 oscillations per two hours to one hour; this change was minute 117 1 84 72.4 345 oscillations per inadvertently incorporated into the new minute 118 ? 0 0.0 431 oscillations per timing mechanism. The eggs in trial G minute 118 ? 0 0.0 were shaken for 1.0 second; those in H for * Hatchability of eggs is expressed as percent of fertile eggs. 0.5 second; and those in I for 1.5 seconds. high frequency hatched better than those These data are presented in Table 2. at low frequency when duration was in An unexplainable occurrence in trial G the range of a few seconds. In order to was the poor hatchability (70.0 percent) check hatchabilities at frequencies higher of the control eggs. When agitation of than 230 oscillations/min., the mechanism very short duration (0.5 sec.) was used in was modified so as to provide shaking at trial H, some of the eggs shaken at 345 115, 216, 345, and 431 oscillations/min. oscillations/min. did hatch. But from the Trials E and F were repetitions of the variability of hatchabilities at 115 and 216 same experimental conditions. Groups of oscillations/min., and from the results of eggs were shaken at each of the above fre- previous trials, it would seem that duraquencies and a group of unturned eggs tion of shaking, in the range of a few secwere included in the tests. The duration of onds, is not a critical factor. shaking was 2 to 3 seconds (the slowest DISCUSSION tray made 6 to 8 excursions). The experiThat these results have been different mental value of these trials was quite good since all the known factors and incuba- from earlier studies of shaking agitation tion conditions operated according to is undoubtedly due to the less severe plan. A complete summary of the results treatment given. It is readily apparent, obtained is given in Table 1. from the above data, that the hatchaIt is noteworthy that the control eggs 2.—Effect of rates of shaking and duration o hatched 93.0 percent; the hatchability of TABLE agitation on the hatchability of chicken eggs (Interval, 1 hour) the 115 and 216 oscillations/min. groups was quite good while 345 and 431 oscillaHatchability* tions/min. proved to be completely fatal. Trial G Trial H Trial I The infertility in the 216 group was very Treatment Duration low. These results suggest that an opti1.0 1.5 0.5 mum frequency exists between 115 and second second seconds 345 oscillations/min.; this optimal fre- Control, turned every 2 hours 69.7 89.6 93.1 Unturned 41.8 48.3 44.7 quency is proximate to 216 oscillations 115 oscillations per minute 59.7 63.2 56.5 /min. 216 oscillations per minute 81.8 63.5 63.3 4.5 345 oscillations per minute 1.6 Rather than to become involved in 431 oscillations per minute modification costs that would be incurred * Hatchability of eggs is expressed as percent of fertile eggs. lot contained from 58 to 70 eggs with fertility not less by examination of the many frequencies thanEach 90 percent.
GEORGIA NOTES
bility of shaken eggs can be made significantly better than unturned eggs provided suitable amplitude, frequency, duration, and interval of shaking are used. The average hatchability of 761 unturned eggs was 33.6 percent, while the average hatchability of 1,214 shaken eggs (including all but totally fatal conditions) was 58.7 percent. It would seem then that shaking agitation does provide the physical stimulus for normal development that is derived from "turning." Especial consideration should be given to the increased hatchability which resulted when the shaken eggs were permitted to be free in the bottoms of the shaking trays. This development introduced another variable into the problem. It was observed that shaken eggs would bunch or clump in the center of the trays. The orientation of the eggs was not uniform, and it seemed that those in the midst of the group did not move as freely as those on the periphery. This situation could be obviated by parallel, shallow, crescentic grooves in the tray bottom at right angles to the direction of movement. The eggs would then be oriented with their long axes perpendicular to the direction of motion. The net result would be that the rows of eggs would roll back and forth in the grooves as the tray shuttled. No attempt was made, during these studies, to observe whether developmental anomalies were produced by the treatment. If such were so, it was not ob-
377
vious among the experimental chicks. The only noticeable characteristic of the chicks from shaken eggs was varying degrees of sticky down which condition is very common among chicks from unturned eggs. SUMMARY The hatchability of chicken eggs subjected to shaking agitation was significantly better than unturned eggs, but not as good as normal control eggs. The average hatchability of 1,214 shaken eggs was 58.7 percent of fertile while that of 761 unturned eggs was 33.0 percent. Normal control eggs hatched 90.5 percent of fertile. The best hatchabilities obtained with shaking agitation were 79.0 percent and 82.0 percent (216 oscillations per minute, 1 to 3 seconds). A suggestion was made by which orientation and movement of shaken eggs could be better controlled. REFERENCES Landauer, W., and L. Baumann, 1943. Rumpless. ness of chicken embryos produced by mechanical shaking of eggs prior to incubation. J. ExptlZool. 93: 51-74. Olsen, M. W., and T. C. Byerly, 1938. Resistance of chicken embryos to mechanical disturbances. J. Agr. Res. 56: 221-226. Seek, P., 1939. Der Einfluss heftiger Erschutterungen auf die Brutfahigkeit des Huhnereies. Arch. f. Geflugelkunde 13: 362-367. Stiles, K. A., and R. L. Watterson, 1937. The effect of jarring upon the embryogeny of chick embryos. Anat. Rec. 70: 7-12.
GEORGIA NOTES A poultry testing station is to be erected at the University of Georgia, Athens. It will be a coopera-
tive project between 13 state experiment stations in the southern region.