Viability of Embryos and of Chicks in Inbred Chickens

THE maintenance of inbred lines depends to a large extent on the viability of embryos and of chicks. An earlier paper (Wilson, 1948) discusses egg production rate and fertility which are also important considerations. The main purpose of this study was to obtain estimates of (1) heritability of hatchability and chick viability, (2) the extent to which these traits are affected by the intensity of inbreeding, and (3) the selection differentials which were made while producing these inbred lines. Hatchability and viability are considered as traits of the individual embryo or chick, while egg production rate and fertility are considered as characteristics of the dam. REVIEW OF LITERATURE Hatchability is the percentage of chicks hatched from a given number of fertile eggs. An excellent summary of the effect of environment and heredity on the hatchability of chicken eggs has been compiled by Landauer (1941). More recently published work includes Water’s . . .