The fungus Aspergillus flavus commonly grows on stored feed ingredients where moisture content is over eleven percent, especially cereal grains (such as maize) and oilcake meal (such as groundnut meal). The aflatoxin called mycotoxin is the specific toxin produced by A. flavus. The toxin itself may remain after all sign of the fungus mould is gone.

Ducks are more vulnerable to the toxin than chicken. In acute forms of the disease, mortality can be as high as 50 percent. Common adverse effects include immunosuppression, reduced growth in young stock and reduced egg production in hens

Aspergillosis

This disease is also called airsaculitis. The fungus Aspergillus fumigatus causes the disease by growing as a fungus in the lungs and interconnected air sacs. The fungus grows on damp litter or feed, and the bird breathes in the spores, which grow into easily visible lesions as green and yellow nodules, which can completely fill the lungs.