It is always your decision, but here are some facts you might want to consider:
Chickens have a strain of coccidia that is different than rabbit coccidia. The chicken coccidia is intestinal rather than hepatic that rabbits can get. This means that chicken coccidia can KILL rabbits! In fact, I got infested with chicken coccidia at the end of 2015 and shut down sales and breeding until I got it out of the rabbitry. This was after loosing 14 of 21 growouts that had been weaned for 3 weeks with no problems. I took a stool sample from one that died for a fecal float at the vet and they called 15 minutes after I left to tell me I was infested.
To get rid of it I had to dose all rabbits with a regimine of Corridor and then torch the cages, j-feeders, water fine and nest boxes, then another round of Corridor treatment and another round of torching.
I finally bred a doe and my first successful litter is now 6 weeks old, 2 weeks from weaning and all are healthy!
Even tho you are going to separate the buns and chickens, there might still be coccidia in the soil/floor of the coop. Also, since the coccidia is transferred through the droppings, you should not let the chickens get on top of the cages! An adult rabbit can get the chicken coccidia and show very few symptoms, but it will still be on their fur, which is how I got infested, so I definitely had my share in the infestation!
Now, in my rabbitry I have hutches that hold cages above the ground and let my chickens roam under the hutches (backyard rabbitry) and there is no cross contamination between my chickens and the rabbits.
I also have two ground lens that I move the does and bucks into in the summer, but I keep the chickens out of there so they don't infest the ground with their coccidia.
So, yes, chickens and rabbits can be housed closely, but a few concerns should be addressed beforehand. Besides, chickens are just plain silly and fun to watch, not to mention the eggs for omelettes!