BackYardChickens Forum

Welcome to chickens and BYC.

The recommendation would be prevention.   It's harder to get rid of them once you have them.   DE is not easy to find and there are many different grades so make sure you aren't steered in the wrong direction.   I live in Western, NY and my TSC does not carry it.   In fact most of the stores around me don't.    I did find a small organic market that has some.   She was pricey but I bought it.    I would do an internet search for it ( food grade or by brand name Perma-Guard ) and you can get it delivered.   
You dust it in the whole coop and nesting area, and if possible provide a dusting bin for your birds with that in it.    If they aren't interested in the bath you can dust them yourselves with it.   
There are many things on this site that will give you opinions, etc. about DE.   I use a small amount, but DE is also to blame for loss of good insects like honey bees so be careful how you use it.   If just in the coop and on chickens, you should be fine.   Just don't go scattering it all over your yard and stuff.

Hope that helps.

We dust our coop and our birds I use an old pantyhose ( I wear gloves) fill the hose with de tie off and get each bird under the wings and around tail vent area I then sift it into the shavings on the floor.  I have lost birds from mites so I tend to go a little overboard.  You will get many answers about how often I do each bird about every 1 1/2 to 2 months then quick sprinkle in the coop inbetween.  Be very careful FOOD GRADE DE ONLY and make sure area is ventilated.
Kasi

Check out www.freshwaterorganics.com/what_is_de.htm  This site will answer any questions you might have.  PermaGuard Codex Food Grade DE is the purest DE on the market!