You can feed everyone a Starter/Grower and offer Oyster Shells in a bowl off on the side.
Rooster as with Chicks and Non-Laying Hens don't do well on layer feed since it is a higher Calcium feed and they have no way to of using up the extra calcium that is in there diet like a hen can.
Roosters, Chicks and Non-Laying Hens that take in too much Calcium can suffer from Kidney Problems and even death.
For those who don't believe me google Calcium Toxicity in poultry also here is the feeding directions for Buckeye Nutrition 20% Layer Feed that has a
Calcium Min. of 3.00% and a Calcium Max of 4.0%;
Quote from Buckeye Nutrition;
40% grain. For lighter weight hens and hens in extremely heavy production, the level of Gold
Standard Laying Crumbles to grain may be increased to 70% Crumbles and 30% grain. Always
maintain a clean, fresh supply of water along with oyster shells and grit for the laying hens. Maintain
the birds in a clean, dry, and draft free environment. For hens to lay at their genetic potential,
daylight or artificial light must be maintained at between 14 and 16 hours per day.
Do not feed Gold Standard Laying Crumbles to any laying hens or young growing birds for extended
periods of time because the higher levels of calcium incorporated into the feed for egg shell
formation may cause harm to the birds.
Chris