The coops Can also be open during the day to ventilate, while they are in the run. They girls will only be closed in at night.
Opening doors during the day does NOT add to the ventilation at night. As the chickens are inside the coop all night, it's even more important to have enough ventilation at night, when they're on the roost and exhaling moisture into the coop.
Recommended minimum is 1 sq ft per bird or 10% of floor space, whichever is greater. Some 1/8" slits aren't going to cut it, you need proper openings to allow for cross air flow.