You can also get the PermaGuard DE through www.earthworkshealth.com if you end up havinf to order online. It is expensive to ship but if you have no other options. i got a 10 pound bag for $18 and another $10 to ship. Also be sure you are getting FOOD GRADE, not just any bug killing DE product.
A cup or so added to shavings in the coop to prevent mites and if you wish you can add to food to help prevent worms naturally. I just add to the shavings as I will probably worm the chickens occasionally. Welcome to BYC!