Okay, I've read many, many of the posts about treatment of chicken lice here on BYC and on other internet sources. But, it's kind of confusing, such as, some people say one works better than the other or don't use this or that type. Most sources mention these products to treat infestations of lice: Sevin dust / Carbaryl Permethrin /Pyrethrium Ivermectin Eprinex/ Ivomectin Some other sources mention: Frontline Dog flea spray/bath dip (Adams) Most sources mention egg withdrawal time of 10-14 days, while others don't even mention it, and others say that you can eat the eggs when using Ivermectin "because it can be used for humans." When I just did a google search for "Ivermectin for lice" - the first result was about "Drug-Resistant Lice Respond Better to Ivermectin" in a human dermatology article; and the next 9 where about using Ivomec for human head lice the 11th result was from poultry-keeper.com (UK source) which stated: PHARMAQ Ivermectin Drops are sold under the Small Animal Exemption Scheme for use in rabbits, Guinea Pigs and ornamental birds. Products licensed under the Small Animal Exemption Scheme are not licensed for use in food producing animals such as chickens and it is for that reason that there is no information relating to the withdrawal period for eggs or meat following use of Ivermectin Drops on poultry.Where there is a licenced alternative, vets should be prescribing the licenced product. To treat worms - Flubenvet is the (only) licenced in feed product. In the absence of licensed alternatives, veterinarians do sometimes prescribe this product for poultry under their own clinical judgement to treat mites, lice and worms in poultry. However, it is only a veterinarian who can advise on such use and it would breach of the veterinary medicines regulations and NOAH code of practice by supporting, or encouraging the use of this product on a non-target species. It is for this reason that we are not recommending you use Ivermectin for this purpose unless it is prescribed by your Vet. I also found these sources that said that deal with Ivomec/ Ivermectin: http://fowlfacts.proboards.com/index.cgi?board=medshhh&action=display&thread=311 https://www.backyardchickens.com/forum/viewtopic.php?pid=2320893 As far as Sevin dust, some people say it works great, and other say it's hard to apply and doesn't work as effectively. From experience with dusting the chickens with DE, it's not something that's easy to get in between the feathers. Permethrin and Pyrethrium are also mentioned, but I think they're powered, too. The other thing is that I'm trying to do "deep litter" for winter warmth, adding cleaning bedding and "stirring it up" when needed. So, I don't want to remove all the litter (which will go on the compost pile in the chicken yard), and many sources say that lice don't live in the environment (although mites do). I've added DE to the nesting boxes, roosts, bedding, dusting bath tub in the coop, but I know that's only a prevenative, not a cure. So, it's hard to know what I should do, since everything has their pros and cons. I'd prefer to use something that we could continue to eat the eggs from the girls, since they've only been laying a little over a month. On the other hand, if I have to, I'd rather do it now and do prevenative from now on, for both external and internal parasites. Just one more thing, while I do see lice and lice eggs on the pullets (most likely came from 4 RIR hens got from another person back in April who I didn't confine and/or treat for lice), they are laying great *, seem to be eating great and otherwise very healthy. (* 4 RS=4 egg/day; 3 EE = 2-3/day; 4 Wy = 2-4/day) Thanks for the advice. I know I need to do something, but not sure what method to use.