Correlated Responses in Body Weight and Egg Production Traits in Chickens Selected for Social Dominance ,

Abstract

Selection was effective in establishing distinct high and low social aggressiveness strains of White Leghorns (WL) studied by Guhl et al. (1960) and of WL and Rhode Island Reds (RIR) as reported by Craig et al. (1965). The highly aggressive strain of Guhl et al. (1960) was heavier (adult) than controls. Preliminary comparisons of body and egg weights, age at first egg and part-year rate of egg production are presented here for strains selected by Craig et al. (1965).The heterogeneous Cornell Control WL and NC-47 RIR randombred populations were sampled as foundation stocks for the selection experiment in 1959. Additional samples were supplied annually from the NC-47 Laboratory for use as unselected controls. Chicks of all strains were hatched concurrently each year and strains within breeds were intermingled during rearing. Pullets were similarly intermingled in laying houses at Kansas State University (KSU). Birds were housed at moderate density, i.e. .