Reaumur and Spallanzani1 used birds as experimental animals in the early days of digestive physiology; other workers on avian gastric digestion include Cheney2, Friedman3 and Long4. The bird lacks the gastric antrum analogous to that in the mammalian species and there is a tubularly shaped glandular stomach called proventriculus which produces the gastric juice5–9. Unlike mammals, which have a separate HCl and pepsin-producing cells5, birds produce HCl and pepsin from the same gastric cells called oxynticopeptic cells5–9. These cells are arranged in tubular glands organised in lobules deep in the proventricular mucosa with central collecting cavities which open on the mucosal surface through ducts5,6.