nuthatched
Orneriness & Co.
Yes, I know Bachelor flocks can be very successful....when they're outside, not in an apartment with no access to even dirt. OP hasn't said how bad the fights are, if it's normal pecking order stuff, that's one thing but if it's all out fight, it could get bloody.Um, I don't think that is always true.
Some people keep bachelor flocks (just roosters, no hens), and they say the roosters fight less when there are no hens to fight over.
So I do not think the lack of hens is the problem.
All chickens, of any gender, will do a bit of "fighting" as they settle the pecking order and maintain it. Some roosters, and even some hens, will just keep picking at each other, and the only peaceful solution is to keep them apart (maybe in separate cages, so they can see & interact but not hurt each other). Some others will get along just fine. And some will sort-of get along when conditions are just right but have troubles at other times (that may be the case here).
I don't think the solution to this issue is keeping them in cages but there's always exceptions.