There are not real magic numbers for how much space you need for chickens. We keep them in so many different conditions, climates, and flock make-ups, and we all use different management techniques. All these affect how much space is needed. Also, it does not matter if the space is in a coop, coop and run, or something else. What matters is how much space is available when they need it.
That is a lot more space than many people on this forum give for four hens. You should be in great shape.