Abstract
1. From 8 weeks of age cockerels and pullets were restricted for 8 or 12 weeks either by rationing, by feeding a low lysine diet or by feeding a diet low in protein but balanced in respect of all amino acids. 2. There was a significant decrease in growth rate of the birds as a result of the restrictive treatments. 3. The dietary treatments affected the rate of uptake of the four amino acids tested—arginine, lysine, histidine and glycine—although the effect was not significant in all cases, neither was it consistent throughout.