Effects of flock age, prestorage heating of eggs, egg position during storage and storage duration on hatchability parameters in layer parent stock

Abstract

This study was carried out to determine the effect of different preincubation storage periods, different prestorage egg treatments and different egg positions during storage on egg weight loss, embryo mortality, hatchability, hatchling weight and chick sex ratio at hatch in layer parent stock. The following factors were analyzed: flock age (24 weeks, 65 weeks), prestorage heating periods (0, 5 hours at 37.8 °C), storage periods (0, 3, 6, 9, 12, 15 days at 15.0 °C) and egg positions (pointed end up, pointed end down). Parent stock age had a significant (p < 0.05) effect on chick weight. This increase in chick size due to advancing age of layer parent stock is attributable to the fact that egg weight significantly (p < 0.05) improved as the age of parent stock increased. Significant differences were found in absolute egg weight loss during the storage period, as a function of flock's age (p < 0.05). Eggs stored with the small end down lost less weight during storage compared with the eggs stored with the small end up. Hatchability of fertile eggs did significantly decline after storage for 9, 12, and 15 days. Flock age, prestorage heating and egg position during storage had no positive or detrimental effect on hatchability of set and fertile eggs and to male:female ratio under the conditions of this study. A flock age x egg position interaction indicated that females, hatched from eggs derived from old flock exhibited a tendency to be heavier when eggs are stored pointed end down whereas the egg position did not affect the female weight when eggs came from young flock.