Backyard chicken spec cards
Measure first, then buy.
Count your hens, get the coop floor and run space, then check the label before you buy.

The numbers we start from
4sq ftCoop floor per standard hen
2sq ftBantams: about half
10sq ftRun space per standard hen
16–24sq ftFloor for 4–6 standard hens
Sources and conditions for each number are on How we research.