QUESTION: I found out that my chickens have feather mites. I wonder what is the best way for removing them ? I heard that the powder dust will cause sterility. Is that true?
No, "Sevin" dust (Carbaryl powder) will NOT cause sterility and will do chickens no harm at all. It will, however, quickly rid them of external parasites. Get some 5% Sevin dust from WalMart's garden center (or many other places) and dust them thoroughly, especially around the vent area. It is available in shaker cans or 5 pound plastic bags which are more economical (about $8-$10). We use it all the time and have never had ANY problem. If there is an area in their pen where they like to take dust baths, dust it heavily with 10% Sevin dust (if you can find it, or 5% if you can't) and sprinkle it around their pen, nest boxes, roosts, etc. You can also provide them with a dusting pan. Place a suitably sized pan or even a cardboard box cut to about 2-4" high in a corner of their pen. Fill it with "play sand" or cat litter or loose dirt and mix in a couple of pounds of Sevin dust. They'll dust themselves daily and you'll never have an external parasite problem. After dusting, your mites will be gone in a few days.