Genotype - hatch interactions as a source of bias in estimating genetic components of variance for eight-week weight in poultry.

Data on 16,557 chicks from 198 sire groups were analyzed to determine the importance of genotype-hatch interactions as sources of bias in the estimation of genetic parameters for eight-week weight in poultry. Estimates of heritability for eight-week weight obtained from a paternal half-sib correlation were .27±.04 and .29±.04 for males and females respectively when the sire component of variance was unconfounded with the sire-hatch interaction variance. If the sire-hatch interaction effects were confounded with the sire effects in an intra-hatch analysis the corresponding estimates of heritability would be .30 and .35 for males and females respectively. No attempt was made to artificially create differences in the hatch environments.The ratio of the dam-hatch interaction variance to the dam component of variance as compared with the sire-hatch interaction variance to the sire component gave a slight indication of a greater degree of importance of the interaction of non-additive genetic-environment effects than additive x environmental effects in the male progeny but not in the female progeny.