If you are getting high humidity then you need to have a coop that is well ventilated.
My coop is the standard 4-5 bird type with a ramp up to the roost area. To improve ventilation, I have taken out the poop tray, saves cleaning up too as poop just drops into the deep litter below. Chickens...
Have you considered a simpler solution of using a big cardboard box or making a wooden container in the yard and filling it with sand/soil/DE so the chickens could have a good dustbath there? Not sure how you are going to shade it from snow though...
Hi all, I'm from Australia (Brisbane to be more specific) and have been keeping 4 backyard chickens for around 8 months now. 2 australorp hybrids/1leghorn/ISA.
Hope to have some fun and informative discussions on here! :D