Heritability of chick viability in a White Wyandotte flock

Abstract

A short account is given of 7 years' breeding for high and low brooder-house viability in a White Wyandotte flock, in which mortality, to 8 weeks of age in most years, varied from almost 50% in the early years to 10% in the last year (1947). When separate sections of the flock were established, the lowviability section showed consistently greater rearing losses than the high-viability section.Brooder house viability appeared to have a relatively low additive heritability, when estimated from such of the records as were suitable, the pooled estimate from differences amongst sires' progenies being only about 0·07. There was definite evidence that mortality was affected by the common maternal origin of full sibs, the heritability estimated from differences amongst full-sib progenies of dams mated to the same sire being significantly higher than that estimated from differences amongst the half-sib progenies of the sires.