They do not make invermectin for chickens. There are really no wormers for laying chickens on the market-thank the FDA and big agribiz for that. Commercial houses have no reason to worm their birds and the FDA doesn't care about backyard flock owners. That's why. You use wormers and antibiotics at your own risk basically. I use Eprinex pour on, when I worm at all. It's easy. Being for cattle, there is no withdrawal for meat or milk, so translated, it's probably fairly safe to eat the eggs, IMO. For a standard size bird, I use a needleless syringe and place 1/4 cc on the skin on the back of the neck. For an extra large standard, like Suede, who is about turkey size, I use 1/2 cc. It's absorbed through the skin and easy to use. A large bottle, which will last a very long time, will cost about $45-50. You then reworm them in a couple of weeks to get any unhatched worm eggs like you'd normally do with any wormer.
