This study was conducted to examine the response of broiler breeder hens to feeds supplemented with synthetic lysine and methionine when fed once or twice daily during peak production. Replacing intact protein with increasing amounts of free lysine and methionine, up to 2.3 g/kg feed, had no effect on feed intake, bodyweight gain, egg weight or efficiency of lysine utilisation, but reduced the crude protein content in the diet up to 3.3 percentage units and improved the efficiency of protein utilisation by 22.3%. However, for each extra gram of dietary free amino acid content/kg diet, the rate of lay and egg output decreased by 3.0% and 2.5 g per day, respectively, and the efficiency of methionine utilisation decreased by 4.3%. There was no interaction between frequency of feeding and amino acid supplementation. These results suggest that free amino acids are not utilised by broiler breeders.