I feed starter/grower 20% protein, with oyster shell in a separate container.
You will get two different answers. Some feed layer, generally 16% protein and higher calcium content and some feed one of these, starter/grower, all flock or flock raiser, these three have 20% protein, with lower calcium, but we provide oyster shell in a separate container. If you have different age chickens, some laying and some not you should use one of the three. Chickens(pullets) that are not laying age, should not really have the extra calcium, it could cause organ damage. Also if you give treats with no protein, it reduces the protein they consume. Chickens need protein to produce eggs and replace feathers when they molt. It's most likely a 50/50 split on here as to what is used.