I've read from a few different research sites that cat litter is not acceptable for rats, but I've heard people here talking about using Yesterday's News with success.
Not to jump on you, but does your rat have a cage mate? I understand that some rats are not social and do not do well with others of their species, but you may not know that most rats are social creatures and they need the company of their own kind. Humans can not give rats the type of interaction that they need in order to lead full, healthy lives. It is like having a human spend his life with no other companion than a dog. While it is a great companion, it is not the same as another of our own species and it cannot communicate with us.
besides yesterday's news they also have some dust-free recycled paper cat litter that i use in the little ratty litter box with no problem. pretty much, if it's dust free, all-natural paper, and unscented, it should be okay.
lol night, i was so confused with your first post. i was like, "um, i thought you loved YN?"
You have to do proper introductions, on neutral territory. Research introducing rats before bringing home your new girl, and it'll be fine.
I have 11 rats in one cage, in my bedroom. They never smell. My best friend runs a rat rescue, and in her basement she has 10-30 rats at any time - they never smell either. There's definitely something wrong with your situation.
Some more questions...
1. What food is she eating?
2. Do you know the exact cage brand/model, or have a picture?
3. What litter are you currently using?
4. Do you spot clean the cage?