There are feeds that could apply to the entire flock.
One name is "Flock feeder" and one is "Flock raiser". This or any 'grower' feed contains less calcium in the feed than any of the 'layer' mixes.
It is thought that the extra calcium would be detrimental to roosters and younger chicks and pullets. The feeds that don't contain the extra calcium can be supplemented with oyster shells. or/and crushed egg shells from your own use. Oyster shells free choice will be ignored by the younger chicks, pullets and roosters.
One other option may be to use a concept like the idea used when calves are given supplemental feeds that the cows would eat unless there was a smaller area with a smaller entry called a creep feeder. So to translate this---an area with entry so small that only your chicks could get in ---the hens would be kept out.... Place the hen feeders at a height that the chicks couldn't reach.