I have 3 does and 1 buck. I hate to have them in cages, and would like to build them a pen on the grass. How big would it need to be, and would it be a good idea? or should I have the buck in a seperate pen? These are mostly just pets, but the buck and one doe came from a friend that used hers as meat rabbits. One doe is a dutch, and the other bunnies are the same size, so they aren't that big.