Egg production records of White Leghorn pullets hatched a t the Poultry Research Centre, Werribee, Vic., during 1947 to 1950 inclusive have been analysed both on a hen-housed (Production Index) and a survivor basis. Estimates of heritability were obtained by two methods: (1) by the analysis of components of variance between families of full sibs and half-sibs; (2) by estimating the intra-sire regression of the mean performance of offspring on dam's performance. Heritability, in the narrow sense, of Production Index during the pullet year is shown to be 23-30 per cent. with a reasonably low standard error, while heritability of survivors' production is slightly lower but not significantly so. Possible reasons are advanced for the low estimates of heritability of survivors' production.
Heritability Studies of Egg Production in the Domestic Fowl