I see. Really the best way to prevent lice and mites is to allow your birds to take dust baths. If the have access to dirt they will create one of their own. If they do not you need to give them an area, I usually use an old washtub and put dry dirt, sand, and I have heard wood ash is excellent, in it. They will do a very good job of keeping themselves clean.
During the winter, because mine spend so much time locked in a barn, I put down DE on the floor. I then cover that with straw.