Quote: Nobody thinks you're trying to have them fight; I think you've taken my reply wrong! I was not condemning you, I was trying to offer my experience with chickens and their social rules. I made that one paragraph bold so you could get to the main point I was trying to make, as I tend to talk a lot to try to get my point across. You haven't done anything wrong, what's happened is some social breakdown that just needs addressing and rectifying. Possibly you should have isolated the rooster for a week but that's not the sole cause of his reaction to the hens and theirs to him. Now that you've given some background it sounds like it is simply a case of them being raised without roosters and him without hens. Which hopefully can be fixed.
It's not a rooster's job to break up fighting with the girls either. Roosters come and go but the flock and its hierarchy remain independent of the males. In my experience breaking up fights between animals rarely work and usually makes more trouble as they never sorted out their pecking order. The subordinate animal also tends to get more aggressive as it assumes you will always show up to protect it... Nothing learnt! Also a rooster who breaks up fights is almost always just getting into it, free for all style, and I cull for that too. I would think there's a few who do that correctly, but overall the roosters I've had who try it just make more trouble.
If you cage him separately and introduce the girls one at a time, starting with the calmest or least aggressive, it should fix up. I would leave him alone for at least two days to settle mentally, probably longer. Then I'd start giving him treats inside the cage where the girls can see it and get in the habit of associating his presence as being linked to something they really want (even if they can't get it yet). This will also give him the chance to see them being calm closer to him as their attention will be on the food, not on fighting this strange 'hen' who's arrived. There will likely be much threatening body language from both sides of the mesh over the food, to start with.
Hopefully at this point he will be getting the idea to make the food call and try to offer food to the hens. Either way, next I'd add the least aggressive hen and make sure she's got somewhere to avoid him if he's not yet out of the idea of fighting. After they've settled for a day or two, all going well, I'd add another not-too-aggressive hen. I would maintain feeding him something the girls want where they can see it, so daily they're seeing he is associated with great food. All going well, gradually I would introduce the other hens one by one, and always offer special treats during introductions so they will not focus on him as they first come into the cage.
That's one idea, but if you have any particular fight-starter hen, most likely your top hen, I might separate her away from the flock all by herself for a few days as he is released into the general population with the girls who should be living with him peacefully by now. This may not be necessary, just watch her attitude as she oggles the food he's got to see if she's still paying too much attention to him. If she is, then taking her out of the social order for a few days (like put her in the cage he was in as he moves with the girls into the cage she was in) should help to reorder things; either way when she comes back out chances are the other girls will be her focus and she theirs as the hierarchy is reestablished. These are just some ideas you can try, nothing's guaranteed. Treats are generally useful to help distract birds when first introduced.
One last thing: in order to reestablish instinct, granulated or powdered kelp works great, but will take at least a week to show and may take as long as six months for some. As a potent nutrient it will help calm them quickly. (You could give it mixed with anything they like, using a little water to bind it, a pinch per bird per day average). Any imbalance or insufficiency (which is the same symptomatically as an oversufficiency, mostly) in the diet will contribute to aggression and anxiety. Kelp will show you if your hens are purebred as it causes proper expression of their actual phenotype; often they show a weaker or diluted version due to not having kelp. It also works for children with Down's syndrome to make them grow up looking normal with much better brain function, if given regularly from a young age; also it works in many people to cause white or gray hair to resume its proper colors. It is a powerful endocrine regulator and contains a full spectrum of necessary vitamins and minerals in the correct balance. It will change your chicken's behaviour for the best. It makes non broodies decide to be mothers though. Full health is worth the trade off of a few eggs I reckon but it's each to their own. Best wishes.
