Hi kinnip, the only way to see if your boy's comb is affected by feeding is to test it. If you can put him (and his girls) in a run by themselves then do so and feed the normal (whatever you feed them) PLUS lots of greens; a mix of silverbeet and lettuce would be good. I also give a mix of white bread that I pull apart into chicken-mouth sized bits, I sprinkle liberally with milk powder, wet with room temp water (cold water if it's hot and warm water if it's cold), mix and serve. Do this for say a week and record his comb colour each day. Then you'll know for sure.
BB.