I realize I have one other data point from inside the secure area where they have two pastures of 50 sq ft. each. I alternate them seeding one and excluding the ladies while they play in the other.
If it is all fresh sprouts they can destroy 50 sq ft. in a few hours (and have a lot of fun...
I fully recognize this is just one data point, and that scaling it up is probably not linear math, but it might still be helpful.
I currently have only 4 chickens. Their Chicken Palace provides just over 400 sq feet of predator-secure space. Most of that has a solid roof but a small amount is...