My buns are all single (since only one us spayed) except for Aroma, Rufus and Obito at the moment, but since Rufus and Obito are only two months old they'll have to move out soon too.
I keep them beside each other though, so they have some company.
Zakura and Aroma can't live side by side as they hate each other, so now Sasuke lives in the middle of both girls, separated from Zakura with a wire wall, and he tends to pick fur of her head...but she sticks her head into his run so I'm not quite sure what's up with those two:? Aroma and her boys are in a indoor cage and can't stick their noses into anyone else's run, but they can see Sasuke. There's only a fee inches separating their cages.
Its rather hard to keep breeding bunnies together, un-neutered males hardly ever gets along, especially if they are to be bred as well, pregnant females too tend to fight, and even if they are separated it could be hard to reintroduce them after the kits are weened. Male and female-pairings are the recepie for disaster unless at least one is neutered.:?
So most breeders I've talked to all have buns living separately, a few may have female groups, but that's rare.