Wow, I didn't know that you could use fleece with rats! I've been using carefresh all this time. Deuce, my current rat, will have to get switched to fleece sometime soon. I know he'll love it now that I heard they can burrow under it. I was just worried about him not being able to dig/burrow like he can with the carefresh, but now I know that he will be able to still! Yay.
Also, fleece is probably much better for their sensitive respiratory tracts. They can develop URI's so easily, because they all carry them, but it takes some sort of external or internal stressor to "activate" it. The carefresh is dusty, so hopefully when I switch him to fleece, it will help.
Thanks Ly and Caviekisses!