Keep your roosters in the same area if possible and if there is no fighting. If you seperate them they will no longer consider each other flock mates. (I learned this the hard way.)
If they aren't fighting and they aren't over breeding the girls 1:7 should be fine. As
@aart said the 1:10 rule doesn't always hold true and depends on individual roosters.
As for the biting; I had one who started that last spring when I'd go into the coop. He was a good rooster otherwise, so a took a very thin stick (switch) in with me for a few days. Whenever he bit me, I'd tap him on the head as if I were pecking him. He stopped within a couple of days of this.
Good luck!