Two injections of sheep red blood cells (0.1 mm, 5%) antigen were done intramuscularly for the evaluation of humoral system responses at 16 and 37 days of age. Four birds from each replicate were randomly selected and blood samples were taken via wing vein at 21st and 42nd day. Thereafter, serum was separated by centrifugation of coagulated blood at 3 000 r/min for 15 min. Immunoglobulin A, M, and G (IgA, IgM, and IgG, respectively) were determined[16].