If you would like something that works with one application and won't set your bird on fire, there is a treatment called NuSTock one can purchase online or at feed stores. If they don't have it, they might order it in for you. The tube lasts a long time, is good for all sorts of skin afflictions/wounds in livestock and pets, works quickly and helps restore new, shiny scales quickly....and is just sulfur, pine tar and mineral oil.
You might also apply it to your roosts as a preventative.
You might also apply it to your roosts as a preventative.