The real goal is to have a dry, carbon matterial that is small in texture so it will cover with out air gaps. Any combination of stuff that fits the bill would work, cedar saw dust would cover but there is a smell change when urine reacts with the oils in the cedar, I don't like the cedar/urine smell even for animal beding.
Some things I have used: soil, shreded leaves, finished compost, sawdust, coffee grounds, heavy paper (short term) dry grass clippings. I think the horse manure after the chickens have pulverized it and it is fully dryed would work to and even plain straw has been used to control the odor of urine buckets when this is used for spraying or fertilizing. And for the turds, keep a little lime around, for when there is a problem with flies or ph adjustment.