As a new chicken mama, I read a lot on here before creating our run. I thought I had done my research. We ended up going with sand in our run. Now 3 weeks later, I just spent the day shoveling it all out. It was very smelly despite frequent cleanings and rakings; I just couldn't ever get all the poop. We are now going deep litter. I put in a bunch of dirt, leaves from the yard, sticks, twigs, and wood chips. I didn't realize how unhappy my chickens were until I saw them in this new and more natural environment. They have been scratching, exploring, and running around all afternoon. Again-- this is just one person's experience, but it may save someone a little bit of money and a lot of work!!