Title: Age of Pullet Effects on Hatching Time, Egg Weight and Hatchability
Abstract:Egg weight, hatching time, and hatchability of young pullet eggs were measured in lines selected for fast and slow hatching times and a control. Eggs were collected from three hatches four weeks apart...Egg weight, hatching time, and hatchability of young pullet eggs were measured in lines selected for fast and slow hatching times and a control. Eggs were collected from three hatches four weeks apart and from four age groups of pullets each differing from the next age by three weeks. Line effects were significant for hatching time and the fast line had significantly smaller egg weight. No difference was observed between lines for hatchability. Significant linear effects of the age groups of the pullets were observed for all three traits and significant quadratic effects were noted for hatching time. As age of pullet increased, hatching time declined and egg weight and hatchability increased. There were significant linear by linear interactions between hatch and age for all traits, because the youngest age groups changed at a faster rate over hatches than did the older age groups. The interaction between selected lines and age groups was not significant for any trait. This result indicates that the genetic differences in hatch time obtained in these lines by selection are genetically uncorrelated with the hatch time differences resulting from age differences, and neither are related to early hatchability. Selection for hatching time reduced the hatching time of the eggs laid by young pullets, but did not increase the hatchability of their eggs.Read More