I have a Petco Rat Manor for my two girls. I use fleece with puppy pads underneath on the shelves, and I put a wooden house on one of the shelves for them to hide in. I also have a hammock available, but they don't seem to use the hammock and seem to sleep in the wooden house instead. I usually change the liners in my cages once a week, and I noticed that there was a lot of peeing under the house. I think what they're doing is sitting in that house a lot, and that's where they're doing most of their peeing, in the same place where they sleep. I am trying to litter train them but I'm not sure I can break them of the peeing habit. One of them was a lone rat for a while and used to sit and hide in another house and pee there. It does have me worried that if this continues it could lead to a respiratory infection. It can't be all that healthy. Do most rats just pee where they sleep? Should I just be changing the liners under the sleeping house more frequently than in the rest of the cage?