This is currently under construction; please pardon its unfinished look.

Welcome to my coop design page! Please also feel free to visit my more general backyard chicken blog at mcornell.googlepages.com/home.
My husband and I have until recently owned 5 chickens, who lived in a chicken tractor that we designed and built 2 years ago. It did a good job, but was fairly small and utilitarian. Then we started having trouble with a predator trying to get in, and despite our best efforts, it eventually did. One of our gals went missing altogether, and another was so severely injured that we had to put her down. Here is the old coop:
I love my chickens, and this made me CRAZY. So I designed and built the Fort Knox of chicken coops (aka Fort Squawks). This is how we did it.
My dad works in the construction field, and was able to bring me a load of scrap/discard building materials. After pawing through it, I decided to build a much larger coop than before, allowing me to address previous design flaws as well as get more chickens (which I had been DYING to do). So here is my preliminary sketch:
As you can see, it's pretty rough, but that's where a dad in construction and a husband in engineering come in handy! I wanted a run big enough to walk into, and a coop that was off the ground- the dimensions were largely dictated by the building materials, as I wanted things to be as easy as possible- i.e. fewer cuts. We started by digging the support posts into the ground.
Then we framed out the actual coop and the run- for the run, we built the bottom frame of 2x4s right along the ground to help with my additional security measures. We used corrugated sheet metal for the roof, and in my overprotectiveness I cut several of the sheets into half-widths and dug them into the ground all the way around the run to keep out digging predators. It extends about a food into the ground and curves outward slightly. It is also nailed securely to the bottom wooden frame of the run, with the chickenwire sandwiched in between. Then we re-filled the trench with dirt (mud, actually, as it started pouring halfway through and I was too stubborn to stop work... but it worked out well, since the mud packed in really solidly).
For easier cleaning we made the floor of the coop of wire, rather than wood, although there are some wooden supports. It took the chickens a little while to get used to it, but they seem fine with it now. We also constructed a sliding wooden floor under that for additional protection from predators and drafts. It slides so we can pull it out to clean.
My dad then framed out a roof (on the ground) and added the metal sheeting. This was SO much easier to do than if we built it on top of the coop! He had the luxury of reaching it from any angle, and it was still light enough that he and I were able to lift it easily and slide it onto the top of the coop, and then secure it with a few screws.
Then , finally FINALLY, we were able to add the plywood walls. This made it look like a real coop at last. I painted it purple because the old coop was so dull and unattractive, and I wanted the new one to be fun and funky to keep me from being sad about the chickens who fell prey to the raccoon.
Some design details we really like:
1. The front door/food hooks. In the old coop we obviously didn't fit into the run, so any problems had to be addressed either by moving the coop or flipping it over, which was inconvenient. Now we can walk right in, and there's no security problem, because the door has a kick panel attached to the trenched-in sheet metal at the bottom. We also don't have to bend and reach to refill or clean the feeder or waterer- we were able to put hooks in the overhead support beams of the frame of the run, and hung the food and water from that. We like to hang them anyway, as it keeps the chickens from knocking them over or getting dirt in them.
2. The coop access. We built the coop at a height that makes it comfortable to get at the interior of the coop and to collect eggs. We built a very sturdy little door on the back of the coop, which allows us to reach the entire inside of the coop- some coops have smaller doors that are convenient for the laying boxes but not for getting to the entire interior for repairs, cleaning, reaching a sick bird, etc.
3. The roof. We pitched the roof appropriately to shed water, leaves, etc that fall on it, and to not be damaged by falling branches, which in our neighborhood is a serious concern. We also used chickenwire along the front of it to provide good ventilation, since the summers tend to be very hot where we live.
4. The location. The coop is far enough back in the yard that it's not obtrusive, but it's easily seen from the house, so we can keep an eye on the chickens when they're in the run. It's also near enough the beehive that I can keep all my beekeeping and chicken-raising paraphernalia conveniently together, but not so near that they interact at all.

The few items I would like to work on would be landscaping a bit more in that area, reinforcing all the edges of the coop from the inside, and building more perches in the run. I might also revamp the nesting boxes, as they seem not to be using them. But I'm very pleased overall, especially now that we picked up 4 more birds to fill out the flock. My flock now has 2 RIRs, a Dominique, an Aurucana, a white Brahma, a black Brahma, and a gold-laced Wyandotte. Here they are: