I would try to treat them at least twice or 3 times 10 days apart to get the live lice and then the newly hatched eggs. Permethrin spray or dust is very good to use. Spinosad, in some products is probably even better, but expensive. But the coop must be treated when all bedding and nest material is removed. Ivermectin which comes in oral or pour-on topical can be used as well. Nothing is easy when medicating chickens because the best treatment is individual. Lice are very bothersome, and make them jumpy and nervous from constantly itching. They will eventually spread to all chickens in the coop. I had chickens for years without lice, and then a good friend brought over a young cockerel of a breed I wanted. Unbeknownst to me, he had lice, and eventually all of my chickens had them.@Eggcessive I was wondering if you could give an opinion on my original question? It would be really appreciated, but don't worry if you're busy.