The question is: Can I comfortably keep five standard-size hens in this setup? My run is 15 X 9 feet. It's predator proof, heavy gauge welded wire mesh on all four sides and on top as well. Sides go down eight inches underground and then go out horizontally from there for another two feet out from the walls. Smaller mesh, lighter gauge wire is overlaid on the walls' bottom three feet all around, to protect against raccoons reaching inside. Above the wire mesh ceiling are several wood beams. On top of the beams are clear plastic corrugated roof panels to keep out the rain and the snow. Those panels are held above the wire mesh ceiling about five inches in the front of the run, and because the beams are smaller towards the back of the run, the roof panels lie slanted so that rain runs off to the back of the run. For the winter, we keep heavy gauge clear plastic shower curtains screwed into the walls studs. So the entire run is windproof. The entire setup is very well ventilated because the roof panels are raised well up off the ceiling by those beams and so the ceiling is really entirely open to fresh air all the time. The coop is a freestanding Little Tikes plastic playhouse with a chicken door that is always open. Always. The floor of the coop and the floor of the run are covered with pine shavings about six inches deep, over the bare earth beneath. Plenty of diatomaceous earth (food grade) raked into the shavings both in the run and in the playhouse. Deep Litter method works GREAT. NEVER any smells. The playhouse has a three foot long roosting board along one side, with the nest box added onto the other side of the playhouse. When we assembled the pieces of the playhouse, we deliberately misaligned the two roof pieces to leave a four-inch wide gap all along the peak of the roof. That makes for excellent ventilation. We installed a large glass picture window on the back of the playhouse. The food and water bowls are outside of the playhouse, in the run. Plus there's always a nippled gallon bottle of water hanging outside in the run. I have two standard size hens and want to get three more now. The playhouse is about 3.5 feet by 4 feet. My question is this: since the run is entirely enclosed, and is rain-proof, and wind proof, and the chickens are inside the playhouse coop ONLY when they are up on the roost board sleeping or in the nest box for laying an egg, can't I calculate the size of the run to figure out how many hens I can keep? I'll add another roosting board, on a right angle to the existing one, so the two boards will be at the same height off the floor. No fighting to sleep higher than the other hens. The internal floor space of the playhouse is about 14 square feet. Dividing that by the usual allotment of 4 sf per bird, equals 3.5 birds. So that means four birds at most. BUT, the internal floor space of the run is 135 sf. Dividing that by 4 sf per bird, equals 33 birds !!! I'll never keep more than five hens. More than five will result in too many eggs for us to eat, store, gift, etc. Well....maybe one more than five will be ok. So I THINK I can keep 5 or even 6 birds with this setup. What do you all think??????? Overall view of the ChickArena run. Plastic shower curtains lining the walls inside as winter wind protection. Food and water bowls. I wash down the outside of the coop once a week; needs it done again. You can see the chicken door at the bottom below the picture window. Black hook in foreground is for hanging one more nippled waterbottle. I only use it when we go out of town for three or four days and I want to be sure that they don't run out of water. View from the front door of the playhouse. You can see the nest box on the right, bit of the roosting board on the left. Boardwalk bridge from nestbox to roost board. Small always-open chicken door on the back bottom wall. Lots of black and white feathers in the floor's shavings cause they're both finishing their molt now. Good view of the roost boards. You can see the playhouse roof gapped for ventilation. Also can see the picture window on the back of the house. Front of the playhouse coop. You can see one of the nippled water bottles hanging outside. Nest box door dropped so you can see inside.