TY JOUR TI HENS IMMUNOGENESIS ORGANS MORPHOLOGY IN EXTREME CONDITIONS OF NON-INFECTIOUS AETIOLOGY KW hens KW morphology KW immunogenesis KW thymus KW bursa of Fabricius KW spleen KW extreme conditions JO Bulletin of KSAU AU Turitsyna, E.G. PY 2012 IS PB Krasnoyarsk State Agrarian University