Recently I upgraded my cage, and changed from using paper bedding to a fleece lining on the floors. I now have four rats, two that are almost adult size and two that are still pups. The problem I'm having is they have been slipping under the fleece and sleeping/relaxing under there. It's a two-level, both have fleece but they primarily stay at the bottom level under the fleece. They have two hides, a large translucent hide and a small coconut hanging from the top of the cage, and a hammock to lay in (although I'm not sure they're aware of what it is yet.) I don't like them spending so much time under the blanket, it bothers me to go hours without seeing them and I hate scaring the new rats when I move the blanket to make sure everyone's happy and accounted for. Do other people have this problem? What can I do to secure the lining or encourage them to just use their hides?