"cover" I don´t even know if this term is used in the chicken world, but it shows you´re into horses!
It´s a good word.
Here I have my Brahma cock with the Brahma hens I want to breed him with...I keep him with about 4. (Actually, one is a brahma-mix non-broody and I know which are her eggs, too. She´s just to keep him quiet when the others are brooding.) He´d quite easily manage more, but I don´t want to breed him to the others, being closely related. I keep my ISAs and Dels in a separate pen for eggs, because things can get confusing when an egg-layer chicken wants to lay her eggs in the brooding hen´s nest. It causes disruption. Being large, Brahmas can and do break their eggs that they´re sitting on, so an added risk would be another hen (or 3) trying to get into the same box.
Is your 'undesirable' rooster really undesirable, or is he a close second? If he´s really undesirable, let him go elsewhere/pot, or if he´s quite good, put him in with a second group for back-up, in case something undesirable happens to your desirable one? Or, of course, you could just get another as needed at a later date......I´m looking out for another decent Brahma cock-bird to 'cover' the other Brahma hens, then I´ll have 3 groups...2 of brahma, 1 of egg-layers. Just what I do..
Edited to add: I just keep a rooster if I want to breed him, otherwise I´m feeding something for nothing. Also, they´re pretty tough (health-wise) birds I find. And my laying hens are quite happy without one. In fact, it lowers the risk of injury. I´ve had 2 hens injured by a cock´s claws, so my breeding hens now wear jackets, and the layers are left as they are. Just another thought on it.