I have four rabbits and they have all loved the shelters. I also foster rabbits for a local rescue and they have them too. It works well indoors for my house bunnies as well as out in the enclosures. None of the 6 rabbits which have road tested the shelters have spent any time in them, they run in and out but all want to sit on top. But it has a slightly rounded roof and smooth surface and some rabbits couldn't get on it, others just slid off. So I have added strips of anti-slip tape (bought online) which has worked really well and they now love it, as Millie is demonstrating.
This reviewer has 4-6 Various pets