They all started together, this behavior I am fairly sure is the small frizzle bantam doing this damage.
I dont think the orpington size wise could have the space to stand on this english game.
I live on cape cod so I am hesitant to separate anyone in fear of them being to cold for winter. I have 2 coops from tractor supply both 4-6 chicken coops.
Hello and welcome to BYC! Glad you joined.
I would rehome the roosters. Chickens do not keep each other warm during. They keep themselves warm by fluffing up their feathers. As long as the coop is very well ventilated, DRY and free from drafts across the roost strong enough to blow open their feathers they will stay warm during winter. You may want to post pictures of your setup as most pre-fab coops are far too small for the number of birds they claim to house as well as poorly designed for ventilation.