Copied from another query:
Nesting boxes - shredded paper - free and easy to replace when soiled.
Coop floor - kiln dried large pine shavings - 8 to 12 inches deep - changed out once per year, dumped into run.
Run floor - wood chips, used pine shavings, dried leaves, yard waste, and basically anything biodegradable - free - 8 - 24 inches deep - composted black gardeners gold gets kicked out of 1/2 hardware fencing and disappears. Level seems to remain constant. Chickens love to dig craters and distribute it for me. I just routinely dump a garbage can full of "browns" into the run. Haven't cleaned it, ever. No mud, bugs, or smell.