Pallets! I'm all the time scavenging these things for various other building projects including but not limited to gates, fences, and blackberry/raspberry trellis systems. I had recently come accross some nice eight foot long pieces and some brand new standard four foot by four foot ones as well as various other sizes via two local businesses that just pile them by their trash bin for disposal.
I started by cutting some posts from Sasafrass on the Northern fence border of the farm (got covered in poison ivy doing it, which I've never had a reaction from until now) and I salvaged a couple of posts from the neighbors throw away pile as well (and a couple "old bones" my reference to dead cedar posts I cut while gathering wood for winter). The dimensions came out to eight foot by twelve foot and required a total of 11 short posts. The roof is made of two eight foot long by four foot wide pallets nailed to the inside of the posts and then nailed accross and to each other via the 2 x 4 support board of the pallets. The sides are two standard sized pallets nailed to the posts and the roof and then covered with heavy duty plywood scavenged from shipping boxes and fastened to the existing structure. The back wall is cobled together by some short three foot by three foot pallets and covered with whatever scavenged lumber I could find from pallets that weren't in great shape in their whole form.
I don't yet have any pictures of the fence which will encompass the yard (this is just a night time shelter, during the day the pigs will be pastured) but the fence is also made up of pallets of various sizes. The fence pallets are recessed into the ground about 6 inches to dissuade the hogs from burrowing out of the enclosure and are reinforced by nailing scab wood between pieces to tighten the joints as well as by using some old greenhouse frame (bent) driven into the ground and woven through the pallets. Since we are dealing with small hogs they will not have the brute physical strength to push their way through the fence and once they bump their nose on the hard surface this should dissuade them from even trying.
Along the fence I will build a feed trough out of two pieces of rough cut two by six nailed together in a V shape and a automatic waterer will be provided in the form of a 50 gallon plastic drum (salvaged from a food processing plant) with a screw in antique pig fountain. The roof will be covered with an old piece of bilboard tarp (verizon wireless side down so as not to give any free advertising to passenger planes above) though you could go old school and simply create a hay stack or thatced type roof which would shed rain water and snow while providing insulation just the same.
More pictures as I finish up the project. We are also converting a small chicken coop, which was once a hog shed on Kim's fathers farm into a secondary hog shed for overflow. More on that soon too!