You wouldn't want to cover them up all the time. It could get to hot for them. And you want some airflow.
I am currently working on making some for my chins cages to use when they are out playing. (So one gender cant see the other). When im done, i will fold it up onto the top of the cage.
It is as safe as fleece itself can be. But it your chins chew/eat on it, then it needs to go. I have one sheet in between my cages that i secured to the top and bottom of the cage. Tight enough where my girls cant rly get it into there cage to mess with it.
