When building a chicken tractor, keep in mind that in any type of poultry containment the old rule of thumb is to provide at least 4 square feet of floor space per bird, although up to 6 square feet might prove beneficial for some of the larger breeds. There should also be plenty of head space to allow for free movement and natural activity.
Chickens have been used frequently to follow cattle across pasture; utilizing some of the lower, finer stemmed plant materials left behind by the true grazers; feeding on some insect life; and even helping to break down manure pats. They will still need to be offered a full feeding of a good laying ration to maintain desired levels of egg laying performance, however.
The challenges will be how to best tend the birds so contained and to protect them from predation. One- x 2-inch or 1- x 1-inch patterned, welded wire is a strong, durable choice, although it will add to the initial cost of construction.
What many call a “chicken tractor” is actually a very old concept used for a very long time in Europe and Great Britain. There they are called “folds” or “arks”. They are rather solidly made structures, often holding up to 20 to 25 birds each and moved about with a draft animal or small tractor. They were of a size that generally allowed for them to be left in place a bit longer than the smaller “chicken tractor” structures now seen in the United States.
A few years ago, we received some SARE grant money to experiment with an A-framed, poultry ark (i.e., a chicken tractor). To best utilize available materials, we built units that were 54 inches wide and 8 feet long. We used treated two-by-fours for framing, ½-inch exterior plywood for the enclosed, nesting/roosting area and 1- x 2-inch wire mesh for the run floor and two angled sides.
Three triangular pieces of plywood were cut with a 54-inch base and a height of 48 inches at the peak. A pophole door, hinged and latched, was cut in each for the birds to move about and to allow better access to the birds. An A-framed housing unit with a width of 54 inches and a length of 4 feet was built on to one end of the frame. The front half was enclosed, sides and bottom, with 1- x 2-inch wire mesh.
Once positioned, I would simply give them a quarter turn to set the run on fresh grass every day for three days. To move them forward I used the old trick of sliding short lengths of 3-inch diameter pipe at front and mid points and pushing them forward on those simple rollers.
Their A-framed shape would all but preclude hoofed stock from rubbing against them and goats from climbing upon them. As winter approached, we brought them close to the house, elevated them on concrete blocks and wintered the birds in snug housing with all-wire sun porches for them to walk out on during even the snowiest of days.
As time passed, we found ways to lighten their weight, a major one being that 2- x 2-inch lumber would have been a good alternative choice for framing. The larger the unit the more difficult it will be to move, and the more birds contained in a single unit the more frequently it will have to be moved. Some units may have to be moved more than once per day if heavily stocked.
In the ark units described above we were able to place breeding groups of up to one male and three to five females of our larger breeds. Such a unit, with a bit of regular housekeeping, should well accommodate six Rhode Island Red hens.