OHhappychicks, if you visit the learning center, you'll find articles on almost every area of chicken care you can possibly imagine

It really is a wonderful resource! Ivomec (ivermectin) doesn't have a stated withdrawal period, but Ive never felt uncomfortable using it on my laying flock -- I just chuck the eggs for 3 weeks after I apply it. The stuff really does kill everything! Mites. intestinal worms... I use it once a year. I personally don't use sevin dust, although I know a lot of people swear by it. I use diatomaceous earth in my coops, sprinkled liberally whenever I do a thorough clean-out. ACV in the water is a big help, and healthy for the chickens besides. (It does have to be the unfiltered kind -- the kind with sediment in the bottle -- not the clear apple cider vinegar you usually use for cooking).
To worm or not to worm is an age-old debate. I know people who have
never wormed their chickens. I also know people who do it four times a year religiously. Here's a good basic article covering different types of worms, signs of infestation, and treatments:
https://www.backyardchickens.com/a/worms-and-worming
And yep, chickens will very seldom lay when molting, and extra protein is a good idea
It took me a long time to figure out the search engine here, so I'll pass this along: if you type in the topic you're looking for, then when the list of results comes up, look on the left hand side of the page -- there's a list (threads, products, reviews, etc...) of links to narrow your search results. If you click "articles" it'll give you a list of the articles about that subject, not a zillion posts

I hope that helps!