We are new to chickens and currently have 3 who have 'dirt' in their run and are free rage all during the day. They love the patch of garden which has bark chippings down so we bought some for the run. But i have been told by a friend of ours who keeps chickens and is a vet that it can have fungus in it that can give them respiritory problems. I can't find anything on here that says it shouldn't be used and i can't stop them enjoying it in the garden! Thanks!