I use mulch. Got a big pile delivered free from the tree-trimming company that is contracted by the electric company to keep tree branches from growing into the wires. I put it in the coops and in the runs. The stuff in the coops gets more poopy, so I rake it out monthly and add it to the garden beds. The stuff in the runs gets scratched around & eventually decomposes on its own. It doesn't get funky or smelly, just biodegrades. I have one pen that gets especially soupy when it rains. I can add an extra load of mulch to thicken it.