How old are these birds? Have they ever been dewormed? If you live in a warm/wet climate parasites are rampant. I'd consider treating for cocci and deworming them as a starting point.
And with only three hens I probably wouldn't keep a rooster at all, especially if he is rough on them. Mating can seem rough to the uninitiated and also when roo's are young. They gain some finesse as they mature. So you will have to be the judge of whether his behavior is actually normal roo behavior or not. If not I'd get rid of him. If you keep any of these three roo's I'd get some more hens.
And with only three hens I probably wouldn't keep a rooster at all, especially if he is rough on them. Mating can seem rough to the uninitiated and also when roo's are young. They gain some finesse as they mature. So you will have to be the judge of whether his behavior is actually normal roo behavior or not. If not I'd get rid of him. If you keep any of these three roo's I'd get some more hens.