From the site you copy and pasted from:
Quote:
None suck blood, so ivermectin will have no effect on them.
-Kathy
casportpony, Kathy says that under her hands on experience, Ivermectin does not kill Lice because the Lice do not suck blood but according to backyardchickens guru "
dawg53" the lice will still bite the hens and ingest the poison from the hens blood. There are different species so you will have to experiment a bit. It didn't work for kathy but depending on the species it may for you! Ive never had lice on mine but will look out now I know what to look for. Perhaps if the hen is completely riddled with lice they all do not get chance to bite the hen so those that have ingested the Ivermectin and die but you cannot see a difference as the others just take their places and in the end the hen may die!
https://www.backyardchickens.com/t/687442/treating-with-ivermectin
http://edis.ifas.ufl.edu/ig140
I was wrong, ivermectin does treat lice. Please accept my apologies for posting misinformation.