A lot of calcium is not good for roosters, but as long as he is not eating oyster shell, in addition to a complete lay ration, he will be as noted above just fine. Roosters can get by with as low as 9% protein, the protein level of scratch in my area. I feed 16 to 20% protein feed to my lay birds. Whereas he does not have to lay an egg most days his requirement is a lot less. My roosters just peck around the feeder and don't consume very much, I suppose chasing hens and crowing does not burn up a lot of calories. It is quite considered or you to enquire concerning his needs, you will make a fine bird keeper.
Best to you and your birds,
RJ