A biometrical study of the mortality of Single-Comb White Leghorn chicks

does not appear. First page follows. Introduction Constitutional fitness in chickens is gauged primarily by four main criteria: hatchability, livability, rate of growth, and egg production (Warren(18)). The desirability of reliable standards for each criterion for breeds of economic importance. is apparent. This investigation deals with the livability of Single Comb White Leghorns, a race of fowls which from the standpoint of numbers equals and perhaps exceeds the numbers of all other breeds combined (Brown(2)). It has been held that the most reliable measure of relative livability is given by the percentage of chicks alive three weeks after hatching (Dunn(7)). This study involves the first two weeks of life during the brooding period. However, two weeks seem to provide sufficient time for chicks to demonstrate the vitality of their particular strain. In the western section of the country most chicks go out into the open air when they are approximately 10 days old.