What to put in coop - Straw, Sand, Pine shavings?

I think it's all personal preference. Our coop has a linoleum floor for easy clean-up and I use straw. I was using pine shavings but switched since straw composts so much faster for our garden. Our run has a dirt floor with straw. Since we don't get much rain in SoCal it's really at the point where I just toss a new chunk of straw in the run when I clean out their coop each Saturday morning and call it good. We free range so most of the waste ends up either in the yard or in the coop when they are asleep.