How do you guys treat mites and lice in highly feathered chickens

[Cheekychook12]

My chickens have a mild case of lice, and I’ve been trying to treat it with various powders and a spray but they don’t go away, I’ve also treated the pen and deep cleaned
I just can’t reach all their feathers
And if I drip them in something their feathers suction and they don’t get wet

 

[Perris]

they have developed resistance to some of the modern preparations because of misuse / overuse.

You could try a traditional method: lard applied to head, vent and under their wings is said to be effective, Robinson Poultry Craft 1911: 172. Since lard is just pork fat, it couldn't do any harm, and may be worth a shot.

 

[Folly's place]

Here permethrin spray works very well, done at night when the birds are roosting. Wear gloves, part the feathers around their vent, under wings, and neck and back. Repeat every seven to ten days, maybe three times.
We battle mites fairly often, brought in by the sparrows and wrens who try for the chicken feed and are out there when our birds free range.
Are you dealing with the same infestation, or new episodes?
Mary