I should have said a pressure hose nozzleMaybe it's something that's not sufficiently emphasized in the advice given to people who want to build a coop- how easier it is if you can grab or just check the birds easily. Confort scooping poop is always mentioned but not necessarily easy access to the chickens themselves.
I said before people here are used to have really high roosts, (probably for predator protection?) , usually at least 6 feet high and up to 10. We inherited such roosts but changed them lately because our chickens had trouble climbing up. It makes a world of difference that we can grab them and check them on all the roosts now, especially with a few invalids.
It's a lot more efficient to check on one, two or three birds every evening once they are on the roost than having to catch them during the day.
Though we did add one temporary roost more difficult to access for us, for the newer hens that didn't want to sleep on the main roost. It's a compromise between their confort and mine.
As for the mites in the coop, I don't know how it's impossible to notice because if you don't see them in the coop (indeed I didn't the first summer as I hadn't heard about them and wasn't especially looking) you can't not see your chickens itching and excessively preening and looking unconfortable.
What kind of pressure washer ? I've been wondering about them but I'm not sure they are safe to use in my coop (cellar with lime washed porous walls).