A couple people provided answers earlier in the thread, I think. A fecal test get you the best answer - to avoid that cost Chicken Keepers try to use a product which may work on more than one species, and do it or another seasonally. Answered by a VET here, is a rotating Best Practices...
Agree - DE is NOT intended for use as an internal de-wormer. DE is sometimes added to stalls/coops, food products in small amounts to prevent critters from hatching out. Becky mixes her own grains and it can help her storage situation...but it seems a wild and potentially harmful theory to...