We have a bunny.
She's a sweet, little bunny... but has been all alone since she came to live with us.
Last week I moved our four January babies to an outside coop and introduced them to living with the bunny. They freaked out a bit at first, but that certainly didn't last long.
Bunnies mark things as "theirs" by rubbing their chin on them. I noticed one late afternoon, when I threw in some celery for snack, that the bunny was rubbing her chin on the backs of the little chickens. I think she thinks she's a mama, and I'm not telling her otherwise.
Other than the bunny gorging on chick feed and the chickens pecking around on bunny treats, all seems to be going well. I even made a swing for the chick kids to play with... but that is freaking them out a little bit too. Perhaps in time they'll embrace the fun of that as well.