I have a female chin who always pees on her shelves. I removed the one she was peeing on and she went to a different one. I ended up having to take most of the selves out and making her some that have tile on them. She still pees but its easier to clean. She also enjoys peeing on top of her tunnel, in her tunnel, in her food cup. I thought there was something wrong with her for the longest time and have taken her to the vet. Done urine analysis, and plenty of other tests, but they cant find anything wrong with her. So I figure she just likes to watch me clean the cage...