Need help with nothern fowl mites

[HappyClucker7]

I discovered a little over a week ago that my bantams have northern fowl mites. Of all the years I've had chickens, I've never once had to deal with these, so I must admit, I'm panicking a little. I've already treated twice with Permethrin powder, but it's done nothing. The mites are still all over my poor chickens' vents and legs (they have feathered feet).
I'm going see if I can get the Martin's Pen and Poultry spray, but none of my local stores carry that, so I would have to order it online. But really I would like to find something I can use now, and not waste any more time. Are there any other treatments I can use?

 

[Wyorp Rock]

Are you treating their housing too?
You should be able to find Permethrin concentrate at feed stores. Mix according to the booklet attached to the bottle.

Treat the housing in 5 day intervals along with the birds. You'll want to clean out your coop each time as well.