Chicken tractor: A lightweight mobile chicken tractor
A lightweight mobile chicken tractor, DIY style
It's over a year since my first chicken tractor prototype (http://www.arpentnourricier.org/la-fabrication-dun-tracteur-a-poules/) came into service. I had the opportunity to see its merits, but also its major design fault. To summarize : it was way too heavy, and the chickens were suffering from cold in winter.
So I decided to make a new one, inspired from examples found on Katy's gallery (http://home.centurytel.net/thecitychicken/tractors.html), but I innovated by learning from the first experience.
Rather than holding forth on the why and how, here is a list of requirements:
- Minimizing the weight - in order to be able to move the henhouse every day.
- Samll wind surface - the wind may blow to 120 km / h on our hill
- Axle with a pair of wheels - to go on uneven ground
- Axle shall be removable - so the structure entirely touches the ground
- The center of gravity moved to the axle - for the majority of the weight to be carried by the wheels
- Solid wood - pannels are aging badly
- No floor - to avoid cleaning
- dimension 2m50 x 1m25 - area for four dwarf chicken with the same width as my cultivated area
- Living area closed on all sides - for cold winter nights
- Possibility to lock the chickens in the living area - to catch them easily without having to go in the henhouse
- Ground nests - chickens prefer to lay eggs on the ground
- No high perches - to avoid injury to the chickens wings when they jump in the dark
- Wired path not covered (or only partially) - to increase the brightness in winter
- Sliding door on the path side - to be partially open when feeding / to allow low recoil / to prevent the chickens to walk on the fence when it is open during the day
- Sliding door on the living area - for the same reasons, and also to get the eggs by opening just a little
- Torsional flexibility - to fit to the ground when the ground is not levelled
- Modular elements which can be replaced easily- structure, doors and roof get old: We have to be able to replace it easily when needed.
Now the requirements are detailed in the different elements.
The triangular lattice structure is essential. This is the most rigid for the lowest weight. The slope is free; I chose 50 ° for a small height and so that the length of the rafters fit the width of the fence that I had (95cm), but I think ultimately that 45 ° is probably the simplest for machining. If one speaks in the vocabulary of carpentry, I have two sole plates (which are used as runners), five trusses supporting a ridge, and three tie-beams to keep the space of sole plates / runners.
Handle and wheels
On the opposite side of the axle, the ridge excess will serve as a pull handle. The sole plates exceed about 20 cm in the front with a runner shape. In the back, they exceed a bit in order to place the axle in the heel.
The tie-beams are not the same height as the sole plates so that it scrap less the ground when moving the henhouse : they are move aside one to two centimeters from the ground.
Corners are placed to increase the structure strength.
The fixations are made with screws. There would be too much work to make fixations by mortise and tenon for a structure exposed to the elements and whose longevity probably does not exceed ten years. If the screws do not oxidize, we can even get them back.
The distance between the trusses is about 60cm.
The main quality of these living area is to have no bottom. So there are no cleaning to do. We take advantage of bird droppings by cultivating behind the passage of the henhouse. In places where one can fear that predators dig under the framework and introduce themselves at night, we should add a very fine mesh netting from below - that could be cleaned with a simple water jet.
The size of 60cm x 120 cm can fit 3 time 60 cm of perches, and two nests. The nests are boards fixed at 45 ° in the angles on the door side. As such, they participate to the squaring. They have no back : we will fill them with straw.
At the top of this space, I intend to put a tank for an automatic watering system, so that it will be a bit protected from direct sunlight, heat and frost.
The roof only covers the living area and a small part of the path. Indeed, I noticed that when it is not raining a lot, the chickens are not looking to get a shelter. By covering only partially, we reduce the weight of the structure, increases the brightness (clear sky instead of dark roof above the birds) which can improve laying eggs in winter and decreases the impression of enclosure (at least in terms of anthropocentric).
The roof is not made of shake (too heavy because of the battens and cover), but with boards. I decided not to line the clapboard to prevent the flow of air through the steps that is madde on the gable. The boards are laid edge to edge, and to avoid too much infiltration of the rain, I beveled the edges to 45°.
The boards are a little over a centimeter thick. As there will be no cover, the weight per square meter of the new coverage will be half the one of the first prototype. And since there will be about half the area covered, this reduces the total weight of the roof by 75%.
To limit the number of screws and to avoid splitting the boards, they are nailed to the structure with thin nails. A more elegant alternative would be to screw on cleats, and then screw the cleats to the structure (but this approach requires pre-positioning the cleats very carefully).
Partition and trapdoor
The partition between the living area and the portion 'meshed path' is used to protect from drafts and the trapdoor keeps the chickens locked when needed.
I did a sliding trapdoor because it seemed to me the most simple way (no need for hinges). The trap is handled using a draw bar rather than pulling a string to prevent it gets stuck due to friction. The door being shifted in the sheltered area, the draw bar is found conveniently on the meshed side : it slides into a mesh of the fence. I do not think it needs to lock: wood on wood frictions will be strong enough so that animals can not open inadvertently (and as long as you do not put the parrot DNA in the genes of chickens, there is no danger that they understand the concept of sliding door).
On the other side of the living area, there is the door leading outside. It is used primarily to access to the nests and get eggs. As it is sliding, you can simply just open a bit : a child can get the eggs without risking letting the chickens out. And as it slides on both sides, we can get the eggs alternately on each side. By opening just a bit more, we have access to all the chickens area and may catch the one you want.
You can also slide the door to remove it completely, and you can even retract it as a showcase library if there is not the necessary distance on the right or left sides to slide it fully. This is useful to clean or arrange the interior and to replace the door.
At the opposite side of the henhouse, there is another door, barred it. It is used to provide food, and open to the chickens if you want to let them run around during the day. It is also a sliding door. It is not big enough for an adult to pass easily: if you want to catch a chicken, you must scare it so that it takes refuge in the living area, then close the door, and use the door on the other end. (Note: I tried - not easy).
If you want to access anywhere (when the chickens are outside) you can simply put the chicken tractor on its side and everything is at hand.
Plan détaillé, usinage et assemblage
The detailed plan is available on a SketchUp file (free of charge 3D drawing program), you can download it by clicking the link above (chickenark.skp):
For machining and assembly, I leave it to each one the reinterpretation from the 3D design. Indeed, everyone does not have the same woodworking tools that I have, and everyone does not necessarily want to work from rough boards.
Acknowledgments, Credits, and Bibliography