I now know thanks to all who responded to my last post that chicken rule of thumb is 8-10 hens per 1 rooster.
That is taken out of context a lot on here and has caused people a lot of unnecessary pain and anguish. You, for example. The commercial hatcheries have found that if they use a rule of thumb of 10 hens per rooster for full sized flocks and 12 to 15 hens per rooster for bantams the pretty much get 100% fertile eggs if they use the pen breeding method. That's just a starting point, they test for fertility and adjust the number of roosters up or down as necessary. A hatchery's business is to produce fertile eggs so fertility is very important to them. The pen breeding method is where you might have 20 roosters in the same pen as 200 or so hens. That ratio has nothing to do with roosters fighting or overbreeding hens.
What do I do now. Will my 3 girls get over bred?
What do you envision "over bred" to look like? It's a scary term. Do you see marauders raping and pillaging as they travel through the countryside? Nothing pleasant about that for the hens.
Your biggest risk is when they are immature adolescents. The boy's hormones take over, he has no control. He is not trying to fertilize eggs that are not being laid, he is wildly mating them because that's how he establishes dominance. The one on top is dominating the one on the bottom, either willingly or by force. The immature girls don't know what is going on but they do know they don't want to be dominated so it is almost always by force. That means it can be violent. If it is violent there is a risk of injury.
One aspect is that the pullet or hen can lose feathers during mating. The male hops on her back and holds on with his claws. That might create a bare spot where he is standing. Part of the mating act is that the male grabs the back of the female's head with his beak. That is a necessary part of mating. The head grab is the girl's signal to instinctively raise her tail put of the way so he can hit the target. There would be no fertile eggs without the head grab. It is not unusual for a few feathers to occasionally be lost during mating. That's not a big deal. The risk if a lot of feathers are lost is that his claws or beak may cut her and cause a wound. Chickens will sometimes (not always but the risk is real) peck at a wound, maybe even becoming cannibals. This can lead to serious injury or death. Often this feather loss looks a lot worse to humans than it really is but I don't dismiss it lightly.
Another possibility is that the girls don't want to be mated but the boys insist. So the girls avoid the boys. Especially if your room is a little tight the girls may stay in the coop while the boy is outside. They may even stay on the roosts to make it harder for him to get to them.
To me these are the aspects of over bred or over mating. Some pullets or hens can lose feathers very easily, most are tougher. I've had some that had brittle feathers. No matter how gentle the cockerel or rooster is the feathers just break really easily, causing a bare back. I typically raise over 40 cockerels and pullets with the flock each year, the ratio being whatever it is based on how many hatch. I have over 3,000 square feet outside for them but every few years a few pullets will spend time in the coop to avoid the boys. That's pretty rare but it does happen. If I had a lot less room I'd expect that to happen a lot more.
These behaviors are pretty typical of immature cockerels and pullets going through puberty. Once they mature the cockerels gain control of their hormones and start acting like a responsible male. The pullets mature (often about the time they start laying) and understand their part in the flock's dynamics. While some kids never grow up your flock usually gets really calm when they do finally mature. Getting them through puberty can be really hard to watch even if nobody gets hurt.
If you really want to keep that boy you may consider housing him where they can see each other but can't physically get to each other for a while until they mature. On this I suggest you go by what you see. Be ready with a plan but a lot of the time there just aren't any of these issues. But there are possibilities.
Do I add more ladies in the spring and hope that the girls i have now will be ok until then?
If you want more hens then get them. But don't get them to solve this problem, if it is even a problem to start with. It's not a solution, it's just an integration you have to get through so an additional problem.
