I am a newbie in the BYC world. Almost two months as a member and loving it. For the past month I have been clearing the underbrush from a small grove of aged pines for my chickens. I intend on starting with five hens and a rooster but want to build my stock to 15 or more as I learn to care for them properly. Now that the undergrowth is cleared the area looks great and is covered with old and fresh pine needles at least 6 inches deep and no weeds or grass. The terrain is relatively flat and level although I do need to use the backhoe to pull the root systems of the scrub-brush. I did mulch all the pine needles and it has rained several times since I started the project. Now the texture is thick as well as plush and teaming with organic life forms i.e. worms, bugs, beetles and such. From what I have read, this is a good thing. On rainy days (and there has been quite a few this past March) I plop my butt down at the computer, log in to BYC and read, and read and read. While I have been spending a considerable amount of time grooming their range it only made sense that I look into building a coop or chicken tractor. Again, BYC to the rescue. To get ideas I studied the many varied varieties and styles of coops and tractors available. I elected to build a chicken tractor to house a minimum of 20 chickens just in case the 15 are added to. After all, I am only starting with six birds. Noting the required space per chicken I decided on an 100 sq. ft. raised tractor/coop with a 240 sq. ft. enclosed run (100 sq. ft. directly below the coop). This may be a bit much but I am new at this and would rather error on the side of providing more than enough room rather than too little. I really enjoyed looking at the many designs offered by the BYC members but in looking at the materials used I knew an undertaking such as mine was highly impractical using conventional back yard construction materials. Weight is the primary concern. Another consideration is that buildings, regardless of size, don’t like to be moved. This is why they are built on foundations or bedrock: I want a mobile tractor and enclosed run for my girls. This is a structural problem. The more a structure is moved the weaker it becomes and I intend on moving my tractor every three to four days. On the low side, that’s more than 90 moves per year. Weight, as I mentioned earlier, is really a big concern: someone’s back ( in this particular case, mine) is required to supply the Missouri mule muscle to move it about. I am 63 and not too terribly fond of huffing and puffing with sweat stinging my eyes just to collect a few eggs: breakfast could easily lose its appeal. Realistically, the eight mile drive to Kroger in a climate controlled vehicle would seem much more practical. Regardless, I want to raise chickens so I need to figure out a way to make this dream come true without hatching a nest full of regrets, misgivings and backaches. I’ve spent many rainy-day hours looking over the many coop and tractor designs offered at BYC. The majority of the more aesthetically pleasing designs used materials such as 2 x 4’s, 4 x 4’s, ½ inch to ¾ inch sheathing or T1-11, hardware cloth, welded mesh and/or chicken wire. Considering the size of my project the weight to strength ratio is unreasonable for a mobile unit using these heavy components. Fortunately I am a retired General Contractor and a lower level Structural Engineer. On the downside, I am not an architect. Certainly not a coop designer. My choice of materials will be light gauge steel, hardware mesh, plastic and non-flammable foam in an effort to keep the weight reasonably low (about 75% below a wood framed structure of comparable size) secure and structurally sound. Light gauge steel has the highest strength-to-weight ratio opposed to the weight to strength ratio of the building materials used in the designs I‘ve viewed to basically build a simple shell. Other benefits of steel are less maintenance and a slower duration of aging. I’ve read about “Coop Fires” so Fire safety is a factor - steel simply doesn't burn or add fuel to the spread of a fire. As a newbie, heat lamps and pine shavings or straw are typically a bad mix so I am electing to minimize my risk. Cost is a factor but I prefer to run the cost over the years and not consider the initial outlay as a hurdle so longevity comes into play. On that note steel is not vulnerable to termites nor vulnerable to any type of fungi or organism, including mold and rot. Stability also comes to mind. A lighter structure with stronger connections results in less seismic force with less probability of damage in high winds or while being transported 90 plus times around the range. Being primarily an “open to the elements" structure, steel offers dimensional stability whereas it does not expand or contract due to atmospheric moisture content. While temperature variances do cause expansion and contraction in steel the movement is negligible and has little effect on the fasteners at joints or stress points. Additionally, stronger connections such as screwed and riveted fasteners versus nails is a no-brainer to me. This will be my shop project and I will be happy to post with pictures as I proceed. In the meantime, if any BYC members know of other coops/tractors being built in this manner I would sincerely appreciate any information or pictures. I’ve looked around and have yet to find a parallel as a guide to help me with my intentions.