It's not for everyone, but chickens are an enormously helpful addition to any urban homestead. They are outstanding weed and bug pickers and they give you eggs to boot! From a prepper point of view, fresh henfruit is a powerful barter item when TSHTF...
A little about the coop. It is designed for five hens; inside has 20 square feet of space, with the external nest boxes adding another 8 square feet or so. The covered sand run has 50 square feet. I have varmint-proofed the run against digging by burying a 2' wide strip of 1/2" mesh hardware cloth around the entire perimiter. Wyle E. Coyote couldn't get in there without explosives.
The coop is double-walled with painted plywood inside and out and insulated with 1 1/2" styrofoam between. The floor is made from concrete board and painted with epoxy paint to make it invulnerable to anything a chicken can produce. The walls are caulked, sealed and painted with porch paint to control roost mites.
The 2x4 roost is level with the windows so the girls can see out. There is plenty of active and passive ventilation to prevent moisture and gaseous ammonia buildup. My compost pile is adjacent to the large cleanout door on the end of the coop. It takes less than five minutes to clean the coop, as I installed a poop board under the roost to accumulate manure.
I have a passive water collection system that harvests rainwater off the roof and stores it in a plastic barrel on the back. There is a standard poultry water dispenser hooked in so the girls are never without water. The coop is wired for 110V AC and I have lights inside and out. I also added a small 150 Watt panel heater this year that turns on at 35 and off at 45. It handles the cold snaps well.
I built the coop between Thanksgiving 2009 and February 2010. We paid cash for everything so there was no credit card interest to add to the cost. To date we have about $1200 into this, and considering what the pre-made coops cost out there, we gave ourselves a real bargain by building from scratch. I used all new materials, but I could have scrounged around for used stuff without too much effort.
That's a lot longer than I intended this to be, and sorry for the novel so early in the morning. Again, I consider this a demonstration project and I'd like nothing more than for someone to take an idea they got from this, and build an even better coop.