permethrin is very non toxic to Animals. The Army used to soak soldiers in it to prevent bugs from getting them. The biggest problem is if they breath it. It is very toxic to the Bugs so it is a very odd and targeted poison.
I have been treating the coops and roosts with a diluted permethrin spray for a while not. It was recommended on California Chickens because you can spray the bottom of the roosts with it. The instructions say you can use it every two weeks in the coops. Mites live in the cracks in wood and come out at night to feed on the birds. If you can kill them in the cracks and stop them from crawling on the roosts, mites will not be as much of a problem.
Why am I feeling the urge to scratch now?
I perm spray my coops once a month while everyone is outside. Its super fast but bedding can still be an issue. I try to do it on non bee days however.

