it depends, for the rabbit in the house that lives in a gunea pig cage, we started out using shavings but when she jumped around the shavings went everywhere!! what a mess to clean up everyday. so now we use straw. if they are outside and the mess isnt that important. shavings would be ok. in my nestboxes, i put down a thin layer of shavings, then straw. in the winter i put down a thicker layer of shavings for insulation. hope this helps!