Effect of social environment and oocyst dose on resistance and immunity to Eimeria tenella challenge

Chickens were exposed to graded doses of a suspension of Eimeria tenella oocysts while in environments of high (HSS) or low (LSS) social stress. Both primary cellular resistance and the sensitization phase of cell-mediated immunity were higher in the HSS environment than in the LSS environment. The manifestation of cell-mediated immunity seems to be inhibited by social stress.