i actually have the fiesty ferret cage. i got it when i only had one chin and he loved it. i did not use the fleece liners on the bottom of the cage because he pees where he wants, so i put the shavings in the slide out bottom tray and used some chin chillers to cover portions of the bottom, where he would stand and eat. but i did use fleece on the top level of wire and it was fine. he also did pee there too though!
now i have a custom built cage and my new rescue resides in the feisty ferret cage.
because he is "brilliant" he uses litter boxes, so i have 2 litters on the bottom & a 12 x 12 marble tile from home depot on the bottom, so ther is little exposed wire bottom. and on the top i still use the fleece.
it is ok for them to have a little wire bottom as long as there is plenty of non wire for them to rest on, which with this cage there is.
i really like the cage, it is easy to get in & out of and i love the slide out tray on the bottom. i know a lot of members love the ferret nation, but when i bought the feisty i was not on this forum and didnt even know there were so many options!