The pen for the rabbits I currently have is a rather big one. Some people may urge against this, but I am keeping all the does in the large area, it is about a twenty-five by twenty on the outside, then running into the barn, it is probably twenty by twenty. I made three separate pens that are smaller for the males. I currently have two males, one pedigree New Zealand White, and a mixture of a New Zealand, and something else.
The rabbits seem to be doing fine together, but sometimes if they seem like they are getting into a little struggle I separate them. They seem to like to run freely instead of being in a more caged area, and seem to be doing fine.