Another opinion here... DE will not kill lice or mites. You need to use a lice/mite dust - what a lot here find effective is Sevin dust. Put some in a plastic grocery bag or small plastic garbage bag, wrap the top of the bag gently around the neck of the bird as high as you can go without getting into the eyes/mouth/etc., and dust the bird thoroughly all around the feathers/wings/vent down to the skin. Do each bird and keep them separate from their living space. Then clean the living space thoroughly and dust it as well being sure to get down into the cracks. I have also heard of using a 10% bleach solution on the living space and thoroughly washing it down. I haven't tried this, but it sounds like it would be even more effective at getting into the cracks and crevices. Be sure to dust any living spaces like dust baths. Repeat in 10 days!
Oh, I saw something yesterday from "Pop" about using a dip for the birds. Pop is good at this stuff and this may be an easier alternative for you! Do a search ...I know it was yesterday. If i can find it, I'll post it here.