Lots of permanent year-round ventilation above tops of walls if possible. Can be soffit, louvered gable end, turbine vent, vented cupola, ridge vent, open screened space between top rafters if a shed roof or a gable roof withouf soffit.
Poop plank
Windows that open on all sides, or maybe all but north sides.
Wall trough or feeder bin that takes at least 50# at a time.
Lights and electrical outlets
Ceiling fan for exhausting heat on really hot days
Water to vicinity of coop, inside run if run is big enough to stand up in.
Guillotine type drop-down pop door closers with overhead cable/cord and pulleys.
If a small coop, a bump-out for nest boxes
Optional storage for supplies and feed, if feasible.
Optional skylight for wintertime solar heat or extra natural light. Able to be blocked in summertime.