If the rossters have gorwn up together, there shouldn't be more than some minor skirmishes. However, the hens will end up looking very poorly with that many roosters constantly trying to mate with them------the roosters' claws will tear the hens' backs up. My advice is to either get rid of 4 of the roosters, or get about 20 more hens! Really, you only need one rooster for every 20 or so hens.