I tried sand in my run here in Portland. Had to sift it almost every day and still had tons of flies. Several of my chickens died while we had sand and then as soon as I switched to deep litter wood chips everything has been great. I haven't had to clean it at all really ( my coop and run are covered which keeps it dry- essential to the deep litter method) and my hens are healthy and happy. It keeps them warm in the winter, and gives them stuff to dig in - more bugs for them to eat. Sand was not fun for them at all.
