I advice against using rodent poison (the green or blue stuff) and diatomaceous earth.  It doesn't matter if the poison is in an enclosed container, the rats can still walk out after they have eaten the poison and anything that eats a poisoned rat (chickens, other pets, and wildlife) will also get poisoned.  Diatomaceous earth is not an effective pesticide during an infestation and may cause more harm than good because it can be very irritating to a chicken's delicate respiratory system.  A Permethrin-based powder or spray is a better option.
Also, regular disinfecting of the coop is not necessary and you definitely don't want to get the coop wet with a pressure washer.  Keep it dry and and scrape poop as needed.
		
		
	 
The permethrin (Frontline) works well, but it is systemic and you are eating the eggs. 
They say it is no problem, but isn't it? The same people who say you can eat permethrin eggs allow smoking, spraying Roundup, and etc. And used to allow DDT, Red Dye #3, Asbestos, and other things -- Everyone is of course free to make their own choices. I think anything that will kill an insect has no place in human tissue. If you deprive the mites of their hiding places and keep everything fairly clean and have some diatomaceous earth for them to roll around in then you won't have to use the pesticide.
Pressure washing with strong agricultural disinfectant does get the place spotlessly clean and is a required practice on commercial poultry farms -- Broiler farms do this every 8 weeks. It rinses off and thus doesn't get into the chickens, their meat, or their eggs.
Wild birds, mice, flies, dirty wellies, feed, etc. Can transfer things like coccidiasis, bird flu, etc. Into the chicken shed. A bit of biosecurity seems sensible. In the UK no-one disinfects eggs, so whatever the chickens step on is also on the eggs, on your hands, in your kitchen, and ultimately on your plate.
Again, not washing the chicken house is a choice people can make on their home flock. I like the chicken house to be very clean so I like waterproof and miteproof walls washed nice and clean a few times a year.  The perch and nestbox can be removed or  better yet washed and dried in the sun. Chickens are dirty little buggers and so are their houses. I think I will continue pressure washing.