Relationship Between Pre-incubation Egg Parameters from Old Breeder Hens, Egg Hatchability and Chick Weight

This experiment was carried out to determine the relationships between some of the physical parameters of the pre-hatched eggs and both chick weight and quality of old breeder hens. In this experiment, 450 hatching eggs obtained from 70 week old white Bovans layer parent stock were used. Three weight groups were formed, lightest being 55-60 g, medium being 61-65 g and heaviest being 66-70 g. Relationships between some of the physical parameters (weight, volume, density and shape index) of hatching eggs and chick weight and quality were investigated for each of the 3 weight groups. Correlations between chick weight and egg weight (p<0.01), egg volume (p<0.01) and egg density (p<0.05) were determined. Relationships between the shape index and chick weight and other physical egg parameters examined were not significant. Chick quality was not affected significantly by any of the physical egg parameters examined. Hatchability of fertile eggs for light, medium and heavy weight groups were 85.5, 86.0 and 83.4%, respectively, hatching yields were 82.7, 82.0 and 80.7%, respectively and fertility were 96.7, 95.3 and 96.7%, respectively. The effect of weight groups on hatchability of fertile eggs, hatch yield, fertility and early and late embryonic mortality was not significant.