The Genetic and Environmental Effects of Hatching Time, Egg Weight and Holding Time on Hatchability

PERCENT hatch of fertile eggs has generally been found to be a trait exhibiting a small amount of additive genetic variance in closed poultry flocks (Crittenden, Bohren and Anderson, 1957), yet large differences between strains maintained under the same environmental conditions have been consistently noted. This may be accounted for by the genetic variation being largely non-additive in nature, and/or because we have not yet learned to measure this complex trait adequately. Bohren, Crittenden and King (1961) have studied the simple relationships between hatch of fertile eggs, hatching time, preincubation storage time and egg weight using limited data. They also showed the necessity for defining percent hatch of fertile eggs as the percent of fertile eggs which hatch up to a specific incubation time, and showed that this is a compound trait made up of embryonic viability, and the characteristic hatching time of the group of eggs incubated. This study…