Invermectin pour on is fine for use with chickens. In fact, all wormers are off-labels uses with chickens anyway, other than Wazine (which kills only roundworms).
For a standard size chicken, you use 5 drops on the back of the neck skin, not one. For a very large rooster, I use 7 drops, like my 14 lb Orpington. For bantams, you do 2-3 drops. You re-apply in two weeks to get later hatching worm eggs. Most folks wait two weeks after applying to eat the eggs, though some wait only one week and some don't wait at all.
I do not use permethrin dust on my chickens so can't speak to that. Invermectin will get lice.