OP, you need a higher protein level. Try 18-22% all flock or maintenance feed with a side of oyster shell and grit. Feeding lay feed to non laying birds (hens, roosters, or chicks) can harm them and slow development. Best of luck :)
You should be feeding maintenance or all flock feed with a protein level of 18-20%. Feeding layer feed to non-laying birds (hens, roosters, chicks) can harm them or slow development. Provide oyatershell on the side.