The basic rule of thumb is one rooster per 10 hens. If you're doing a special breeding project, then you can go down to one rooster per 5-6 hens, but watch them for over breeding. This isn't just my opinion, but the opinions of many people.
If you only have two hens for one rooster, then you really have to watch the stress levels, and the amount of feathers on their backs.
If you only have two hens for one rooster, then you really have to watch the stress levels, and the amount of feathers on their backs.