Small-intestinal cryptosporidiosis in a chicken.

Severe small-intestinal cryptosporidiosis was diagnosed in a chicken that had diarrhea, was weak, and had failed to thrive. Intestine segments also were parasitized by Eimeria sp. and bacteria. Disseminated foci of malignant lymphocytes were present in several organs. Spontaneously occurring intestinal cryptosporidiosis has not been reported in chickens.