You can use carpet squares to cover the wire floors or linoleum squares. The carpet squares tend to absorb a lot of odor and will need to be replaced every few months. And it's very difficult to keep clean, especially if your ferret has any "out of the litterbox" accidents. The odor of the accident cannot always be totally gotten rid of, so this may cause the ferret to continually go back to that spot and use it as a bathroom(they'll usually return to an area that smells of where they've gone potty before...even if the odor is very faint). I prefer the linoleum squares. They don't absorb odors and they are easy to clean up after an accident. Plus, the linoleum stays nice and cool which will give the ferret something to lay on during the warmer months to keep cool. I would say cover the ramps too, just to be on the safe side.
No ferrets are not natural chewers like rodents, though some have been known to chew on things like rubber, foam, etc. There are more non-chewing ferrets than chewing ones--yeah, that makes sense
lol
If you get one that likes to chew, you can alleviate the problem by offering them products like cheweasels, foamy fries, or kong toys.
