Clay, I fully understand what you are asking.
That is part of the reason I originally said (way back a bunch of posts ago )I wouldn't need windows up there because that whole eave line, along with the lower edges along the walls of the henhouse will have continuous vented soffit panels which I am positive will allow more than enough ventilation....the idea of adding the windows just makes it more appealing but I don't believe they are needed for ventilation purposes.
Buster, I have no idea how many hens .....I'd say around 20-25.