If you have enough yard space, have a walk-in coop rather than that 'under the coop' space. How will you get under there? Cleaning, getting eggs, critters, chickens, dead critters, whatever. Have shade some other way!!!
Mary
Build big! A Woods coop is wonderful; second is a walk-in shed, modified as a coop. Least expensive is a cattle panel hoop coop, built predator proof.
If you are limited by law to a few hens, that's one thing. If you can have however many you want, 'chicken math' will strike, and you will...