Thank u sooo much! great post!We have many crested breeds and have to treat for mites. The very best thing that we have found that works every single time is Frontline spray. You can get it online, from a vet, or possibly a pet store. It comes in a spray bottle and lasts a loooong time if you follow this dosing. Put it in a contact rewetting drop bottle, visine dropper bottle, etc. Somone I know also puts it in a medicine cup and then uses a q-tip dipped in it to apply. You need to get the medicine down to and onto the skin for it to work. One drop in the crest or back of head. One drop under each wing in the armpit, and one at the base of the tail near the vent. This will kill most within 24 hrs, if it's really bad it might take 48. After 3 or 4 days you can wash out the crud that they built around the feather bases. Wait a day or two after washing and then reapply the drops to keep it from coming back. You can also use this same stuff for scaly leg mites, just spray it right on the legs. I'll include a link to show you exactly what you are looking for. It looks pricey, but like I said, it will last a very long time and it was well worth the price.
http://www.amazon.com/Frontline-Spray-500mL/dp/B0002J1G02