I don't know a whole lot about bunnies, but I know goats are very prone to getting cocci (which I suppose is why lots of peopl say you shouldn't keep goats and chickens together). Not sure if this would be an issue with your rabbit??? I keep a dwarf goat in with my chickens and haven't had any problems, he came from a home where he roamed with chickens also. He's still very young ( and neutered), but I would certainly think my chickens are smaller than you bunny, and they co-exist just fine. The only issue I had in the beginnig was keeping the goat out of the chicken feed, one high shelf later and that was resolved. Good luck!!!