Thrush (Mycosis of the Digestive Tract): In young turkey’s poults, thrush may cause heavy brooder-house losses. In chickens, the infection generally appears with other conditions. The disease, more common in turkeys, is caused by a yeast-like mold called Candida albicans. Signs are not characteristic but an autopsy usually reveals lesions in the crop. There may be whitish, opaque areas on the crop lining but, in extreme cases, the lesion may cover the entire crop. The mouth and esophagus may show ulcer-like patches. Frequently, these molds are isolated from the intestines of birds with nonspecific enteritis.

Mycotoxicosis: Many molds—even the nonpathogenic ones—may produce toxins that can cause serious losses in poultry. Among these molds are many species of Alternaria, Penicillium and Aspergillus. Ideal conditions for outbreaks of mycotoxicosis occur where birds have access to moldy grain, or when some ingredients in their feed are moldy. Spilled feed around waterers plus the warmth needed for brooding help the molds to grow rapidly and produce toxins. Young birds 4 to 8 weeks of age are most generally affected.

They become droopy and pale and often have diarrhea. Mycotoxicosis sometimes causes a condition in chickens called "hemorrhagic syndrome" or "a plastic anemia." The condition is characterized by intramuscular hemorrhages, especially in the breast, legs and intestines. Generally, the blood is very thin and pale. The bone marrow becomes pale and yellowish, in many cases completely devoid of all normal red color.