Ivermectin horse paste topically under
each wing of each hen - the paste comes in a large syringe tube at the feed store. If the hen weighs 2 lbs then only one Q-tip drop under
each wing on the actual skin, if the hen weighs 4 lbs then two Q-tip drops under
each wing on the actual skin, you get the idea - one paste drop for every pound of bird. I have only 4 hens so this is an easy treatment for me to do. Some people think Ivermectin paste is useless for worming but I've used it for almost 5 yrs and my flock's fecal tests have never tested positive for either worms or cocci. I also use Rooster Booster's worming feed to add to our flock's regular feed as a follow-up for a month after worming with Ivermectin. Everyone does or uses something different for worming but if it ain't broke I'm not fixing it. My method has worked fine for me. Everything I do I run by my vet so I take his word as final confirmation. He exercises on the side of caution, has worked in the poultry industry, and loves chickens - especially mine, I might add

-- he's always pulling out his phone to snap pics of my Silkies!
Do research on different wormer products till you find one that suits your taste, so to speak. There are a lot of wormer recommendations on BYC and at first it boggled my mind all the input I was getting from so many people. One thing you want to check is that the wormer you choose covers more than just roundworms. Apparently there are different types of worms and maybe one product may only cover one or two types so read your labels. Tapeworm is a separate issue and uses a different type of medicine or vet care.
GL!