These Chicken Tractor is built for Oklahoma, we have temperatures from 105 to -10 degrees. I have raised chickens and built their pens for years. Unlike metal, wood keeps cool in the summer and warm in the winter, you must make sure it is sealed for it to last for years and look good. All animals must have a good amount of shade and you cant always keep your pens under trees. So there must be a cover over most of their run, if not all of it. Also very important is the wire used in these pens, todays poultry wire is so thin a dog or a large coon can rip it apart. I only use the 1x2 heavy 14 gauge steal wire that is use to make rabbit cages or a 17 gauge hex fence wire, todays chicken wire is 20 gauge (the larger the number the smaller the wire). No chicken wire or hardware cloth ever, I have heard of to many stories of predators ripping it apart and killing the animals inside. The way you figure how many chickens you can put in a pen is by the length of the roost. Standard chickens need between 8 to 12 inches of roost per bird. If you have a 4 foot perch, the most birds that can roost is 6, and that is only the smaller layers. If you have real large birds you can only fit 4 birds if that. Birds need a covered run that is 4 to 8 square feet per bird, that is 2x 2 to 2x 4 per bird. Chickens must not be over crowed because they will kill each other, even if they have fresh grass everyday. I built my first coop like this about 5 years ago. I always use the first one so I can make any improvements on the next one. This 2 story design is great because it gives you twice the floor space. No crawling in a 4 tall pen to get to an egg in the corner or to get to the feed pan, with the built-in feeder, just open the door and pour in the feed. The top door is big enough to lean into so you can reach everything in the top part, if a egg is laid in the bottom corner, just push the pen over the top of the egg and pick it up. With the wire bottom it stays cooler in the summer, when the cooler shaded air raises up into the top part and with the back window open it lets the heat out. Even in the winter it will stay warmer because you can shut the back window and keep the heat inside. If the temperatures drops below freezing, just add a little hay on the wire and that will keep them warm, you can even hang a light from the top so they will lay all winter. With the wire bottom there is no cleaning the box, all poop just falls to the ground, you just have to move the pen over a few feet to new grass. I also have them with 6 long runs on each side, photos of them soon on my website. Basic chicken tractor $750 that includes: 76 long x 4 wide x 5 tall ~ 2 story ~ Holds up to 12 standard chickens or up to 15 bantams 55 square feet of actual floor space Sold in bare wood ready for you to stain 2 handles Feed door with built-in feeder Egg door with 3 nests Back window with wire cover and wood door that can shut up tight. 1 x 2 heavy gauge wire All exposed lumber is treated not just stained so it wont rot All zinc hardware - screws no nails Ladder 2 x 4 x 75 long wooden perch Extras: $100 ~ Weather proofing 25 year stain, your choice of 1 color $25 ~ Second stain color $125 ~ 4 solid rubber 10 tires with steel brackets Check out my website at OkieCritters.com or call me at 918-273-2515 for more info.