EDIT from title, it's definitely lice, not mites. We got 15, 5 month old Black Australorp pullets about 1.5 months ago from someone on craigslist who had many, many hens for sale. All but 2 are laying well daily. We lost one to a vent prolapse, and now several (if not all) have lice There were no signs except poopy tail feathers which have been increasing, and now several chickens have them. They also have a lot of watery poop, always have but I looked up normal poops and it seemed fine? They are all eating well/drinking well, foraging well, no lethargy, etc so I didn't think there was anything wrong with them and now it's bad. They all like to dustbath in sand/wood ash in a tire so I thought that would help prevent mites/lice. I am a new chicken owner so I've been quickly trying to research how best to deal with it, and have a few questions: 1) Sounds silly, but can we still eat eggs from hens that have lice? It seems like it should be okay, but sounds super disgusting and I'm not sure I want to right now, but hate to waste eggs since that's the reason we got them. 2) I know I need to clean out the coop/nesting boxes well and change/throw out the bedding, but how often am I going to need to do that? 3) Do I need to clean the coop with soapy water/spray? It's spring here and always raining/cloudy lately, so I don't really want to add more moisture to the coop, it won't dry out very well at all. 4) I trimmed some of their poopy tail feathers today and was thinking I should bathe them, but will that make anything worse? A few of their rear ends are very disgusting. 5) Is Diatomaceous Earth enough to treat them with? I would prefer not to use chemicals, but I also want this gone quickly. 6) I do have some Ivermectin horse paste 1.87% which I know plenty of people say not to use because it's hard to dose, but it seems like the tiniest piece (like a grain of sand) wouldn't hurt to put between their shoulders? 7) How long do I need to treat them? Will I know they are healed when I don't see any lice/eggs, or do I treat much longer than that? 8) Could they have had lice when I got them from the person who raised them or have I done something wrong allowing this to happen? Thank you!