X10The main concern I have is how well the birds will be able to maneuver. If they jump off the roost, are they going to crash into a wall and get injured? I assume you plan on having the roost down the 9 foot side, and not a bunch of two foot long roosts, right? And the roosting bars need to have a foot of clearance from the wall it's set nearest. That means you will have a roosting bar running right down the middle of the coop. That's going to make cleaning a real challenge. And it won't leave any room for a ladder to help them down, off the roost.
2 feet just isn't wide enough. Either clean out the rest of the shed, or build something else for the chickens.