OK, you've seen the "thumb rules" -
per bird:
4 sq ft "house"
1/4 nesting box (per hens, round up)
1' roosting bar
1 sq ft free ventilation 24/7/365
10 sq ft "run"
All together I have about 400 sq ft of "house" (including the grow-out box in the barn) and two runs - the small one attached to the grow out pen is about 320 sq ft, while the main run which has got to be closer to 2300, maybe 2400 sq ft (40-something by 50 or 60-something, and not a good rectangle).  
The first house is two levels, 8'x12', which involves a number of mistakes I would not make a second time. The 
second house is shared with the goats. The third "house" is a top hinge door in the side of my barn wall, which leads to a section set aside for little chickens. Measures 13.5 x 4' or maybe 16.5 x 4" (I can never remember) with a 4' pony wall partitioning it from the rest of the barn, and another 3' of bird netting "wall" above that to keep 'em where they belong.  Access for humans is via a full height door into the space.
 My flock free ranges an area of about 4.5 acres, of which 
about 1.75 acres is pasture.
The main space is currently shared with three goats.  With the ducks, I typically maintain a flock between 55 and 70, year round.