I don't advise concrete floors. If you don'thave a sealor on the concrete, it absorbs moisture (concrete isporous). It's also quite rough on rabbit's feet (but it is good fortheir nails). I kept mine on concrete for 2 days once and my poor boyhad majorly irritated sore hocks, mine are living in a pen in thegarage nowbut I completely cover the concrete with cardboardand newspaper, it's easier on their feet.