Wow! I'm blown away that the last two responses were from Lake Oswego and Yacolt. I'm in Amboy! They weren't kidding when they said small world.
I have not wormed these chickens either. My main symptoms (for identifying the pest) are little pale things clinging to the vent, feather loss that looks worse than just molting and some birds not growing feather back well, and I did have one hen die of unknown causes (on the nest box) but she looked in good health, I think she may have been egg bound (we were not home).
I do think these are lice not mites.
Pharm Girl I wish you were online now or I'd PM you, we are going by Lake Oswego today on a different errand. I would have taken you up on that offer to share. That is very generous of you however, I'd like to know how that product ends up working out for you. We don't have Coastal Farm and Gardens here, just Wilco or mail order of course, or Pioneer Feed.