don't know ours was spay on stuff.
if its coopers spot on i treat with 0.2ml per hen after two days if the bugs are still there and its a big hen up it to 0.5ml but don't repeat the dose. powder with a lice powder at the same time. keep the delay on eggs the same.
you can get small syringes from the vet. please remember that nether have been approved for hens. this means that they have not paid to have it tested on them. also ware gloves as hens flap more than sheep or dogs your more likely to get it on yourself. the back of the neck is a good spot for dosing a they find it harder to get to. don't forget to check for any second hatch in a few weeks. and clean there House out at the same time.