Last year we raised Cornish Rock Giants in a chicken tractor. It was 5x10 (2 ft tall) and held 25 birds at a time. I was not pleased with how much they dirtied the ground in the latter weeks, and the tractor could have been moved two or three times a day but it was a big job - it was heavy and I had to lay bricks and rocks all along the skirt, which had to be tied up when I moved the tractor or they would catch. So I only moved it once a day. They had no room to run around and were dirty and lame by the end days. Although they tasted fabulous we felt we could do better by them. So this year I built a temporary coop: plywood floor raised off the ground (on old fence posts laid flat), a wall of straw bales all around (save for an opening for the door) then stuck my chicken tractor on top. The whole thing is covered with a tarp and there is a heat lamp inside. The floor is straw bedding and so far I'm just piling more on as it gets dirty (sort of a deep bed method). Its about 5x10 feet. I have a panel for a door that i put on at night and take off in the morning. Right now there are 21 birds but they will be joined by 26 more when the next batch moves out of their brooder. For their run there are four "quadrants" around the coop which I plan to rotate them through. Each quadrant is like a maze (but with no dead ends) such that no part is wider than 5 feet. I got the idea from a chicken moat but it's not in a circle. This keeps out the raptors, which is our main predator here. I also ran flagging tape along the top between fences for added insurance. Each quadrant is about 20 x 20 feet but it seems like more because of the way the corridors wind around, giving the chickens more places to explore, and more incentive to move around. The meaties are 3 weeks old now and have been outside for a week. They seem to enjoy being outside. I love watching them running around, pecking and scratching, and taking dust baths. They are acting like "real" chickens! We still have a few weeks to go, and lots more growing, but so far we are really pleased with this setup and feel the birds are much better off this way.