Devona
Chirping
I use topical ivermectin for external bugs of any type. A drop on the skin under each wing, a drop on each side of the vent and a drop on the neck where they can't reach while preening. Works great ! If you have bantams ( I do ) on them a drop under each wing and maybe one by the vent if you see bugs or eggs sacs at the base of the feathers.
Make sure they have acsess to a dust bath.
I ordered the ivermectin when I noticed the problem, but they said it would take s week to be delivered, and being the impatient person I am, couldn't wait that long. I had read about someone using the shampoo so I decided to try it, and the pet shop was on my daily route, so I bought it and gave my poor hens a bath