I put 3-4inches of sand as a base. On top a thin layer of straw and pine shavings. On top of that pine mulch nuggets from lowes, hay and grass weed clippings about 4-5 inches deep. There are all these little dugouts where they dig to the sand and wallow around. I am thinking of partitioning off a section for bathing only. Theyfound that in hot weather the sand is cooler under all that deep litter so they cool down plusbath.