I'm confused. Searching for a new chicken coop or a shed that holds up to 3 ducks, 4 hens, 18 chickens (25 in all) I already have 3x5 2 floor coop which I'll be using that one too. I figured I'll get 5x8 quaker that holds up to 20-25 chickens as they advertised but if I need 4 sq ft per chic then that is 100 sq ft. What is wrong with this math ?