Effect of flock age, cessation of egg turning, and turning frequency through the second week of incubation on hatchability of broiler hatching eggs.
Hatching eggs from commercial broiler breeder flocks at 34 and 37 wk of age (young) and at 59 and 61 wk of age (old) were stored for 2 d at 18 degrees C and 75% RH and then subjected to turning frequencies of 24 or 96 times daily up to 8, 10, 12, or 14 d of incubation at standard conditions to determine if an increased turning frequency would facilitate an early cessation of turning. Turning was discontinued after the respective days were completed. Eggs remained in setter trays until combined at 18 d to complete hatching in a single machine. The young flocks exhibited significantly better fertile hatchability, as expected, but there was no overall effect due to differences in cessation of turning from 8 to 14 d of incubation (range 88.9 to 89.2%). However, turning 96 times daily produced significantly better fertile hatchability that was largely due to a significant interaction of flock age and turning frequency; the beneficial effect of increased turning frequency, largely reduced late-embryonic mortality, was more evident in the eggs from the older flocks.
Elibol
O
O
Department of Animal Science, Faculty of Agriculture, University of Ankara, Ankara 06110, Turkey.
Brake
J
J
D000375:Aging / Q000502:physiology*; D000383:Agriculture / Q000379:methods; D000818:Animals; D002642:Chick Embryo / Q000254:growth & development / Q000502:physiology*; D002645:Chickens / Q000502:physiology*; D005260:Female; D008297:Male; D010063:Ovum / Q000502:physiology*; D013997:Time Factors