I have a barred Rock hen that has a bare spot below her vent. I noticed that there are little white spots at the base of her feathers, I have heard these are mite eggs. I have spray that helps get rid of them so I sprayed that on her. I've also been spraying all hens with that once a week and using seven dust every once in a while in their dust bath, and completely cleaned out their coop this spring. So I am not sure where the mites are coming from, if someone could explain this to me that would be great! I didn't see anything crawling on her just the eggs. I also put Apple cider vinegar in their water.