I asked because the only lice I have seen are the tan ones, and those cannot be treated with ivermectin. I tried several times and gave way more than the suggest amount every way possible (orally, by injection and topically). Each time it made no difference in the amount of lice.
Yes indeed...I know what you speak of...the flat quick moving, but slow enough to watch, straw colored lice, fairly large in size for a lice...lays small white eggs at base of feather shafts. Poultry Dust successfully treats those nicely...switch up with Sevin to prevent resistance...dust in 10 to 14 day increments to catch new hatches...life was good. I was only bothered with them once or twice on a couple of birds. I never used Ivermectin for those as I too had heard it is less successful on that type of lice since it is not a blood eater or live skin eater but eats feathers and dander and dead skin cells, stuff the Ivermectin drug doesn't penetrate well as it is supplied by the blood.
I too used to think it was either poultry lice (the straw colored ones) or northern mite (small moving pepper spots)....now I've seen other stuff birds can harbor.