I have used DE for years with all my animals. Cats, dogs, horses, and chicken I myself use it daily. It works great. I place a small amount right in the feed, I dust the area where they sun bath and sprinkle it directly on them. The biggest thing you have to watch for is that it say FOOD GRADE on the packageing. There are a few different kinds for pool filters and gardening. Double check it say s food grade. I'm a little concerned because it say "food chemical --------grade" all the stuff I get just says FOOD GRADE. other wise it is perfectly safe to use on chickens. It is completely natural and can not hurt them. DE food grade can be ingusted and works as a natural pest control. provents worms, lice, ticks, mites or what ever else then can get.