1. Sixty individually-caged birds, each of two stocks, were offered either a complete diet (11.2 MJ ME, 173 g crude protein and 32 g Ca per kilogram) or a choice between the same diet and ground barley. All diets were offered ad libitum from 41 to 56 weeks of age. 2. Weight gain, rate of lay, mean egg weight egg output, shell thickness and total food intake were unaffected by the treatments in either stock. 3. The mean intake of the complete diet was 825 and 845 g/kg of total intake with standard deviations between individuals of 73 and 61 g/kg respectively in the two stocks. 4. In birds given a choice of diet the one selected was related to output (P<0-01).