The hutch that my bunny is in has a nesting box built on the side, my bunny stays in it a lot of the time, is this okay or should I close it off until breeding?
***** Karen Sez ***** This is okay. The space likely gives the bunny a sense of safety and security. It also might be a bit warmer in the winter if it is somewhat enclosed and can entrap the bunny's body heat in the small space.
Just ensure that you can clean it out regularly if necessary. If you put a bit of shavings in there, you don't want the rabbit using it for a litter box, especially if you intend her to eventually use it for a kindling box. But usually rabbits keep their resting spots (like this one) very clean; hopefully she will too.