I don't think a rabbit should be allowed to run loose in the yard with no fence to keep it home, but I don't think the OP was talking about just turning the rabbits loose. Rabbits won't come home to roost at night like chickens. Not having a fence, even just during the day, is just not an option if you want to keep them around. As with chickens, cage free does not mean they are just left to fend for themselves or just turned loose with absolutely no confinement. I know many people who keep rabbits with chickens, and it works great for them and for me. That's not saying it will work for everyone, and their are things to consider like parasite control and predator protection. With proper sanitation and treatment for cocci if needed, there is usually not a problem. I have never had a problem with cocci, I watch carefully for signs as keeping rabbits on the ground, with chickens or not, increases the chances of infection. Another thing to consider is safety of the kits if you are breeding. If your chickens have access to the rabbit nest boxes, they will likely eat the little ones. You also have to make sure that your rabbits can't dig out. A lot of colony rabbit people bury their fence a few feet in the ground and allow the rabbits to dig burrows (which protects the kits from the chickens). I can't allow them to dig, so the bottom of my pen is lined with chicken wire. Since I removed my does (who do most of the digging) I am thinking about taking up the chicken wire to see how it goes.
Edited by rizq - 10/13/08 at 9:27am
I also make sure both the chickens and the rabbits have their own places to go where they can get away from each other. Mine are in with our bantams so I use chick feeders, which the rabbits can't get their noses far enough into to get much chicken feed. My chickens mostly leave the rabbit feed alone (which is kept in a 1 lb chicken feeder), they don't seem to like it. Chicken feed IS unhealthy for rabbits. Rabbits have a very difficult time processing corn and it can lead to digestive problems. The extra calcium shouldn't be a problem, they will excrete what their body doesn't use, but they really shouldn't eat much chicken feed. Small amounts won't hurt them though.
Just because a rabbit is in a pen and not a small cage does not mean you can't handle them. My rabbits have the run of the 12 x 32 pen with the bantams and are very sweet and easy to handle. They come up to me in groups and stand up on my legs begging to be picked up and held. If you socialize them when they are young, you will be fine. Depending on your purpose for the rabbits (i.e. if you raise them for meat and not just pets), you may not care if you can handle them easily.
Having rabbits in a more natural setting, rather than a cage, is VERY good for the rabbits, just as it is for the chickens. Being able to graze on natural foods and be able to move and stretch and play is also very good for them, just like chickens. Of course, they need protection from the predators, just like the chickens. It gives them something to do, they are MUCH happier. I believe they are much healthier as well, as they get plenty of exercise. They muscle out better and are grow better. Just because they don't lay eggs doesn't mean you don't need to consider what is truly best (and most natural, which IMO is best) for the rabbit, especially if they are meat rabbits and what goes into them eventually goes into you. They don't have to lay eggs to deserve the best care.
ETA: I have read this several times, and no matter how it word it I think it comes across a bit argumentative, this is not my intention and I hope I don't sound like I am trying to cause a problem. I am just trying to say that it works for me and several others I know of. There are challenges, but they can be overcome. I agree completely that rabbits should not just be allowed to run loose in the yard, but I don't think that's what the OP had in mind.