I have two does from the same litter that were raised together for many months. They displayed some dominance type behaviors when they were in the original cage together. Nothing violent. When the weather got below triple digits, I moved them outdoors into separate cages side by side. I placed them in a run for exercise and one immediately started going after the other. I separated them from the pen and gave them the whole back yard which is quite large. There was fur flying immediately. They went at each other like fighting kangaroos. I've never seen anything like it. It didn't take long for them having their own cages before they decided they didn't want to share ANY space together. I now give each bunny a separate day of the week for their "backyard time". The interesting thing is that they spend some time under the other's cage. I've given up trying to figure them out.