I would just make sure the chickens can't sit on the cage and poop over the rabbit. Rabbits can get cocci easy from chickens. Otherwise they can share a building just fine. A friend of mine was breeding rabbits and chickens for showing and had them all in 1 building. The rabbit pens lined one side of the coop and the roosts the other. The mesh went all the way to the ceiling to prevent chickens from sitting on top of rabbit pens. I've also attached painter's plastic or tarps to the top of pens in my coop to keep chickens from pooping on quail or other chickens I've sperated.
Someone will come along here and maybe have the exact post, but this was discussed once before and a couple of people said their rabbits had killed their chickens out of the blue after living together for a while. Seemed strange but happened to at least two people on here. Maybe better to not take a chance...don't know.
While it can work it is not the best idea. Rabbits may suddenly decide to kill their room mates. They also are prone to cocci like I said. Chickens can peck at rabbits as well. It may work for one person, it may work for years, but there is a pretty good risk of something going wrong eventually. I don't see it as worth the risk.
Quote:Coccidia is species specific. Chicken coccidiosis is not contaigious to any other species or vice versa.
Are you sure about that? I thought they could get it from other birds. If it was truly species specific wouldn't most urban chickens have nothing to worry about since they are typically the first chickens ever raised on that land?