Chicken Tractor
I keep chickens in the garden. They live in a device called a chicken tractor or chicken ark (depending on which side of the Atlantic you come from). It has an indoor coop and an outdoor run. The run is 4'x5'x2' and the coop is 2'x4'. Exactly how many chickens this houses depends on the age and breed of the birds. Four to ten sq.ft. per bird in the run is a rough estimate.
The tractor can be moved to a new patch of lawn each day. This is useful because it means the birds can't destroy the grass and no one area gets saturated in chicken shit.
I used hardware mesh (not chicken wire) to keep raccoons out. There is large 3 inch netting on the run floor to stop predators burrowing underneath. There is access to the run through a flap on the top. See ChickCam for progress of the new additions!