You'll need to clean out the coop, and nest boxes, and dispose of or burn all of the litter. Wash down the coop. You'll need to do this at least twice about a week apart b/c the first cleaning will not kill any of the eggs that are yet to hatch. if you use the bomb, be sure to use it when they are OUT of the coop. Read several threads about treatment for red mites. Have you checked your birds? Have you seen red mites? The red mites live in the cracks and crevasses in the coop, and even in the litter, coming out at night to feed on the chickens. You won't see them on the chickens unless you check after dark. The first thing you need to do is a daylight inspection of your chickens to be sure they don't have lice or feather mites. Check under wings, back of neck, around the vent. Then do an inspection of the coop to see if you can find any red mites. The nymphal stage is extremely tiny, and you might need a magnifying glass to see them. Try wrapping a piece of white cloth around the roost, and check it in the morning for red mites or blood stains. An other indication is that you will hear the chickens stomping their feet on the roost at night. Red mites love to hang out in the nest box. You might even find some crawling on the eggs. Find out what you're dealing first, then deal with it accordingly. What is in this bomb? You'll want to choose the least toxic treatment that will still solve the problem.