Gallibacterium anatis is a Gram-negative bacteria that is part of the Pasteurellaceae family. It is found in a wide range of different bird species. It is considered a normal inhibitor of the trachea and cloaca of healthy chickens. However it has also been associated with cases of acute salpingitis, peritonitis, hepatitis, septicemia, oophoritis, follicle degeneration, enteritis, pericarditis, and upper respiratory tract lesions in chickens.
G. anatis is often isolated together with E. coli. Predisposing factors include concurrent infection, seasonal changes, abrupt weather changes or extremes, age, immune status, genetics, hormonal influences, and stress.