Selective breeding of chickens for corticosterone response to social stress.

Selection for either a high or low corticosterone response to social stress produced lines that differ for this trait. Comparisons between the selected lines and various crosses showed additive and nonadditive genetic variation but no maternal effects for response to social stressors as measured by heterophil/lymphocyte ratios. When the lines selected for divergent responses to social stressors were exposed to nonsocial stressors, they responded similarly.