Deep bedding with wood chips, shavings, and plant materials, is best. Some grass clipping, hay, straw, and more shavings. If you scatter treats on it, the birds dig in and help make a nice base. Newer folks with small flocks, dry weather, and daily poop scooping, will use sand, at least for a while. Deep bedding, cleaned out once or twice a year, is so much more user friendly! Mary