Response of early and late feathering broilers to various stressors

Growth and responses to potential stressors were measured in early (k+) and late (K) feathering chicks from a common commercial broiler parent stock. Body weights were not different at 3, 10, or 49 days of age with ad libitum feeding, but K/K cockerels were heavier than k+/k+ ones at 24, 38, and 52 days of age with alternate day feeding. No differences in heterophil:lymphocyte ratios were found between K/K and k+/k+ individuals whether they were moved to a new environment or remained in familiar surroundings. Antibody response to sheep erythrocyte antigens was not different in K/w and k+/w pullets. Typical husbandry procedures that might be considered as mild stressors did not elicit physiological stress responses in these meat-type chickens.