I wouldn't recommend it for those with rabbit colonies with all the bunnies on the ground, as the coccidiosis issue could become a serious problem with the poultry fouling the water.
Yes! Water has to be tended to. I put iodine in my water, as it helps keep any metal toxicity at bay, and keeping the water supply itself clean. (WARNING: Iodine can be easily over-dosed when taken internally so if anyone uses this method only use a tiny amount!)
HOWEVER, I read this info when I first started researching rabbits and it wasn't exactly accurate, in my short experience, it's another myth. I have a small space and there is a lot of chicken poop, but only where they roost. The bunnies naturally avoid these spaces anyways, and prefer to hang out in the cleaner main areas. Every few days I can get in there and cover the poop with old hay, every few weeks I scoop it all out and add it to the compost or mulch directly into the garden. I haven't seen any issues with this 'deep litter colony on-ground' method! Just had to add my experience.
The main issue, I have concluded, is the toxic commercial chicken feed which would be both dangerous when wet, and would render the dried poop's dust extreme volatile. This isn't a danger from the actual bacteria though, rather it is the bacteria/"parasite" which become present in toxic diets, consuming and cleaning dead cellular tissue - rather than "attacking" living healthy cells.
Having a deep litter method controls dust extremely well, as it keeps moisture and a cooling/heating effect which naturally circulates the air, catches lingering dust, and integrates it into the system.