That's why i liked adding the bug-killer to the oil base. It really did the job quickly. The oil/vasaline soaked into the crust and brought the pyrmethrin with it. A lot of this hen's scales were standing straight up when i did the treatment, and now with the exception of a few they are layed back down. For the people medicine for mites/scabies, it only takes one application. So by adding the pyrmethrin to the oil/vasaline you are laying down a barrier that they can not survive on, oxygen or not! I did it once a week for 3 weeks, just to be sure, but i did not have to do it every day, and it seemed to bring immediate relief. The scales took a little while to lay back down, but that is because they were so far out of place. The only drawback is waiting to eat the eggs. (I think package directions say 2 weeks) So i followed package directions and did not eat eggs from her until the time was up after her last dose.