A circadian rhythm of calcium intake in the domestic fowl.
Synopsis Observations on the food and calcium intake of six laying hens indicate that when the opportunity is provided, the fowl can control these parameters independently. The results suggest that calcium intake is regulated on an hour‐to‐hour basis by the needs of egg formation and anticipates maximal calcium requirement. Detailed records obtained from a single bird in a Skinner box suggest that calcium intake is controlled by a response to ovulation. This could be either a hormonal or a neural response.