For awhile now my chickens feathers have been fraying. Some have told me that it might be mites. I've put DE Diaotamasious Earth or how ever you spell it all over the coop and run and have dusted my birds in it. I do it about every two weeks and their feathers are continuing to fray. I asked the local feed store for advice and they recommended Permecterin II to spray on them and this does not seem to help much either. A few times I have seen dirty bottoms but this does not happen often and is usually fixed with a dusting. I do live in the desert and it is very dusty, but any recommendations on how to stop this? I also have one bird that her feathers a coming apart altogether and the shaft is just left ( the white one on her tail, I am grateful that her new feathers are coming in) . I also wanted to mention that I have a 7 chickens all different breeds. Here are pictures of the white one and then of one of the others but her's do not seem to be as bad as the others. If it's not mites any suggestions as to what is causing this and how I can get rid of it? I also wanted to mention that other wise they seem to be in good health. Good poop and good egg production and are very active and curious!