I use DE. It dries up poop and reduces odor. It kills flies. I have also used Seven's Dust to kill lice/mites. I do the shake and bake method. Put some seven's dust in a bag, put chicken in up to it's neck and gently roll it! Ha ha.. I also make sure to get it under their wings. I have seen the mites die within minutes. I do this again a week later just to be sure I get all the hatching lice/mites, too.
You can also go to the store and buy the dog lice, ticks, flea and mite drops. Make sure you get the one that includes lice and mites! Get the one for the biggest dogs as they all cost the same and you get so much more. Put the liquid in a bowl and use a dropper of the stuff on the back of your chickens neck. Two drops for big chickens, one for younger or bantam chickens! Works great to keep those lice/mites off for months. In fact, I have never had trouble with them again!
You will also have to dust the coop and roosts. Good way is to clean out all old straw, wood chips. Sprinkle with dust, let sit for 20 minutes. Then take a leaf blower and blow it all around. This helps get the dust in all the crevices. You should wear eye protectors and something over you mouth and nose.
As far as I know, you can still eat the eggs. I did and nothing is wr...o..??/n.....tyhehak...g with me! You can always feed those eggs back to the chickens for a few days if you are worried about it.