If you live in the east in some states, Custom Milling has reps all over, plus in Ohio, I think. I just tonight found a rep in my area after always having to drive an hour and paying $10 more than I paid tonight for it. Here is their link-in the site, is a listing of the states and their reps in each state. Maybe there's one near you. They sell the Permagard Food Grade DE. It must say on the bag "Food Chemical Codex Grade" or it isn't suitable to use the way we chicken people need to use it. I dust my birds with it, put it in feed, put it in their shavings, under the straw in the nestboxes, etc:
http://www.custommilling.com/index.php?option=com_content&task=section&id=5&Itemid=27
http://www.custommilling.com/index.php?option=com_content&task=section&id=5&Itemid=27