if you are trying to get rid of mites, I would use food-grade diatomaceous earth- I get mine in a 50-pound bag at the local farm supply. The mites are in your coop so just dunking or trying to kill them just on the chicken won't do you any good. You will need to strip down your coop, clean or even better - replace bars and disinfect boxes. I would do this while your chickens are free ranging or out in the run. Then dust down your bars, coop, boxes, and the entire flock with dia earth. It's the only thing that has helped me control the mites here in the tropics

hope this helps!!