[Breed-dependent anomalies in ornamental birds].

Following a definition of the terms pet bird and domestication, and a description of important mechanisms which may have played a role during domestication, a short review is given on the various changes that occurred and have been used selectively by humans: changes in body size, skin and feathers, skull, metabolisms, and the central nervous system including behavior and disturbances of behavior. Implications for animal welfare are considered.