Umm
not sure of the entire question, but I was advised to use Sevin dust 5% to dust coop, walls and birds and some in the run to kill lice. The bag method was pretty messy (bird in plastic bag up to neck with powder in it, pop bag from various angles to distribute on feathers and skin; rub some on neck and head with soft cloth), so next time I'm going to try knee-high hosiery with some Sevin in it and dust them.
Have you found lice on your birds or looking to prevent? There are also other products recommended by BYCers like Adams flea and tick spray, and natural products like DE
some more input from others, please.