Macroscopic pathological findings in an ABV4-inoculated cockatiel. Bar size = 1 cm; F = peritoneal fat; H = heart; L = right liver lobe; V = ventriculus; A) Markedly reduced pectoral muscle mass and subcutaneous fat stores are clearly seen in an ABV4-inoculated cockatiel (cockatiel 3). B) Normal pectoral muscle mass and subcutaneous fat stores in a control bird (cockatiel 5). C) The peritoneal cavity of cockatiel 3, showing a severely distended and thin-walled proventriculus (arrows) that is visible well beyond the left liver lobe. The ventriculus is mildly distended and the peritoneal fat is dramatically reduced. D) In cockatiel 5, the proventriculus is of normal size, and; therefore, completely hidden behind the left liver lobe. Note the abundant peritoneal fat stores. E) The proventriculus and intestine of cockatiel 3. The thin wall has been cut, exposing a large amount of undigested seeds. Whole seeds are also visible through the intestinal wall.