How big is the coop it’s self? The coop, for standard chicken recommendations, is 4’ for coop each, and 10’ per run. I’d say 2 birds, but that might even be a bit small, considering that you would probably want 28’ for run and coop to house 2 birds.
The usual guidelines are that each adult, standard-sized hen needs:
4 square feet in the coop,
10 square feet in the run,
1 linear foot of roost,
and 1 square foot of permanent, 24/7/365 ventilation -- the pop door that's closed at night and any windows that are closed in the winter don't count.