Effects of induced moulting on immune responses of hens

1. The potential for induced moult to be a stressor and therefore alter the immune response in hens was examined. Spent hens from White Leghorn and White Rock layer flocks were induced into a moult by withdrawal of food and the effects on the humoral and cellular immune responses of these birds were examined. 2. Lymphocyte numbers were lower in moulted birds compared with nonmoulted controls. 3. Antibody responses to sheep red blood cells or Brucella abortus antigen were largely unaffected. 4. The delayed type hypersensitivity response to the skin sensitiser dinitrofluorobenzene (DNFB) was depressed during the period of food withdrawal but recovered when feeding resumed. 5. Induced moulting probably has a negative effect on the cellular component of the immune system of the moulted birds.