Some hatchery factors involved in early chick mortality.

Observations made in a commerical broiler hatchery revealed that chicks hatched over a period of 48 hours. Chick mortality to 10 days of age was 3.2% for those hatched at the commencement of the hatch, 1.2% for those hatched at peak of hatch and 52.9% for those hatched at the end of hatching. Chicks hatched early were more prone to dehydration while late hatching chicks had a higher incidence of leg weakness. Chicks held for 48 hours in hatcher machines lost 12.5% to 21.7% of their hatching weight and 79.4% of the hatching weight of the yolk sac. Normal 10-day mortality from this hatchery in winter months was observed to be 2.4% but was reduced to 1.2% when staggered setting times of donor flocks was employed by removing chicks from the machines 3 hours after 100% hatch, but was increased to 5.6% by holding chicks in the hatchery in chick boxes for 24 hours at 70 degrees C.