We have a total of 38: Barred Rocks, Rhode Island Reds, New Hampshire Reds, Buffs, and Aracanas.
Ours are in the Coup-Mahal, as I call it. They have a 8' x 10' shed and a 18'W x 40'L x 8'H enclosure.
The coup has power inside and keeps a heated base water jug in the winter and has interior lights set on a timer, year round. There is an attic space where we store up to 600 lbs of feed as well as oyster shell and hay. We have a four bay laying box and two 10 foot and one 6 foot roosting bars. The floor has a very thick coating of epoxy paint, the kind that you use to coat garage floors, etc.
Outside, I built a feeder box that has a four foot trough which, by standard practice is not quite large enough but it seems to work just fine here. The feeder self feeds, by gravity, and holds about 150 lbs of layer pellets.
We feed them a mix of layer pellets and cracked corn. The layer pellets are Du-More brand from TSC. We used to use Blue Seal but the TSC brand looks identical, has the same ingredients, and is $12/50lbs while the Blue Seal is $20/50lbs. For the winter, they get 100lbs of layer pellets mixed with 50lbs of cracked corn (TSC $8/50lbs) but for the summer we switch to cracked corn and fresh grass.
We get 1 day old chicks from Murray McMurray Hatchery. We get a new batch every couple years so we always have at least two different age ranges at all times. Until the chicks grown into pullets, we keep them segregated, via chicken wire fencing, inside the coup under a heat lamp. Once they are big enough to defend themselves or fast enough to run away, they are mixed into the rest of the flock. Since they are visible as they grow, we think that it helps with integration as we've not had many issues once the age groups mix together.