I located a local source of food grade DE and thought I'd give it a try for my 10 week old pullets to take dust baths. At first, not knowing any better (since I am new at all things chicken <g>), I made a depression in the sand bottomed run and poured the bag into it. Occurred to me after additional reading that the DE is better off being mixed a little bit into the sand; so I removed the 'bowl' of DE I had added and mixed some into the sand. This morning when I let my chickens out of the coop into the run, they were really 'going to town' on the DE - reminded me of pigs, joyously, rolling around in a mud puddle. I would never had the chance to try it if I hadn't found the local source of food grade DE. Most of the mail order methods involved postage more expensive (or at least as expensive) as the product I was buying. So if there are any fence-sitters on using DE in your substrate; just wanted to let you know that your chickens will love the stuff!