Studies in the absorption and excretion of certain minerals by poultry. II. Changes in the composition of food material as it moves along the alimentary tract of the hen

One laying and one non-laying bird were fed a normal calcium ration, and one laying and one non-laying bird were fed a low calcium ration. Four hours after feeding the birds were killed, and the contents of the various portions of the alimentary tract were analysed and compared with the composition of the original food. 2. The p H of the crop contents is influenced by the p H of the food. The lowest p H value is given by the gizzard contents, but after that there is a gradual rise, until, by the time the 4th segment of the small intestine is reached, the p H. is almost constant at about 6·8 for all birds.