This is why I needed your help! I want my coop to be able to hold up to 10 chickens at night, comfortably. That's why I got fed up with my prefab, I felt bad that I have one so I'm trying to fix my mistakes now.
I asked a friend of mine to check for something where they are so hopefully she'll find something. I'll keep looking today as well
10 adult, standard-size hens would need 40 square feet. Half that for bantams is 20 square feet.
That's 4x5 feet. I'm about to clock in for work so I don't have time to do the metric conversion.