Hello, my husband and I are fairly new to keeping chickens. We have had a parasite problem since summer. We have used DE and Sevin on the most resistant infestations. We have one han who has never gained weight who keeps getting reinfected with mites or lice. I want to dose her with Ivermectin except I am not sure where to get it or how to give it to her. I know we shouldn't eat any of her eggs for two weeks but apart from that what I have found on the forum doesn't answer my very basic questions. Thank you.