We normally recommend one rooster for every ten hens or so. In a large flock, there is often more than one rooster, with no problems. In smaller flocks, it's a greater risk. However, many breeders keep significantly greater numbers of roosters with their girls--one rooster for every two, or one for every five. read more
There is no law against it but you will have a bald hen who will be mounted by the roosters at least 10 times a day. you will have 10 roosters who will fight over that one hens and will try to kill one another daily. read more
I have one rooster. I have read that 8-10 hens per rooster is ideal. However, a woman who has raised chickens for years tells me that if you have only one rooster, three hens is about right. That's what I have, 3 hens, plus one Bantie hen who is too tiny for my rooster to mate with. So far there have been no bared backs. read more