Sub Acre Ranching: Chicken/Rabbit Tractors

One of the most perplexing challenges of my Sub Acre Agriculture project will be to consistently and sustainably increase fertility in the soils to optimize yields over time. While this can be done exclusively through green manure cover crops, it is more efficient to combine a planned cover crop rotation with livestock manures. Andy Lee states in his book Chicken Tractor, that while he was at Intervale Center in Vermont he saw yields increase in one year with manure to the levels it took 4-5 years with (very) heavy compost applications. As this system is designed to be used in small landholdings, specifically medium to large Suburban yards, traditional livestock such as goats, horses, and cattle are not really an option. That leaves smaller critters -specifically poultry and rabbits.

Rabbits are a great option if you want to eat them for meat: they breed like, er, rabbits, they have manageable feed needs, and their manure is “cold” which makes for great vermi-compost and can even be directly applied to your beds (though wait before applying raw manure to any food crops!). If, like us, you are not into eating your livestock you may go the route that Patti, the Garden Girl has chosen and raise Angora’s for fiber while still getting all the fertility benefits of the manure. She keeps them in rabbit “tractors”, portable pens that are sized to fit in her small raised beds so they apply their manure directly onto her gardens. Slick! Plus they are dang cute and very gentle around little ‘uns. Think of them as a functional petting zoo!

We will be using chickens as I want to leverage several very useful attributes of being a chicken: scratching for food, pooping, laying eggs, and eating bugs. When confined to a small space, chickens will scratch to bare soil in their search for seeds and critters, all the while manuring as they go. In a traditional chicken pen this leads to hardpan and toxic levels of nitrates which can kill the soil. The trick is to let the chickens stay put long enough to prep the ground without damaging it-in other words you need to move the birds. Enter the Chicken Tractor. Much like Patti’s rabbit tractors, chicken tractors are moveable pens that house, feed/water, and protect the chickens while confining them to a specific area. In our case the beds are planned to be 3×40’. So our “tractors” will be 3.5′ x 12′-ish with roughly 10′ exposed to the ground allowing the birds to be moved down the beds eating, scratching, laying, de-pesting, and manuring as they go. The tractor will be mounted on 2×4 skids, perhaps with wheels on one end if it gets too heavy -I want it to be one person portable, and will be wrapped in poultry wire with a hutch for laying on one end.

Initially the Sub Acre Market Garden was designed to include the chickens within the rotation-moved as needed to strip off a crop and prep the ground for the next. This was proving to be very complicated: Where would the chickens go from late June to August when the majority of the beds were in crop? Would the chickens be able to scratch down the perennial covers like red clover? How in the heck would I maneuver the tractor into the middle of a diversified bed? Lots of problems. Thinking within this rotational framework was proving fruitless, and was sapping critical time and energy, so I broke down the rotation and rethought it from scratch. The solution I came up with was permitted by the fact that I have virtually unlimited space at the farm (20 acre farm, .1 acre garden). I now plan on laying out 2 gardens that mirror each other. The first will be tilled this spring with the 48″ tiller on the owners Kubota -this should be the only time that tines hit soil in this project. The beds will then be planted on a modified rotation, basically removing the perennial covers (Red Clover/Alfalfa) that were intended to add fertility-replacing them with the missing legumes like dry and snap beans. Covers will still be used, but they will be annuals like buckwheat and oats to keep the soil covered in between plantings in the Spring/Fall beds. Come fall the beds will be sowed with a rye/vetch or other winter hardy mix.

Meanwhile in the “mirror bed” will be the more locus for actually building fertility. Cover crops, unless left in for more than a year, typically only maintain fertility when used in a vegetable rotation. Taking the “mirror” bed out of production will allow it to be under cover for a full year, building critical root systems, while also adding fertility and building soil ecology through active additions of animal manures. Goal is to add at least .25% organic matter each rotation. Not only will this boost yields, it will also sequester roughly 2.5 tons of CO2 per acre!

To get things going, I will do a rough sheet mulch to remove the pasture grasses, and that will then be planted with a PVO mix (Peas, Vetch, Oats) on parts and Sudangrass on others to build fertility and smother any remaining plants. Planting both (and any others that you can recommend) I will be able to experiment with a variety of crops for ease of incorporation and their ability to sync with this system. Into this I will use a system of mowing (hopefully with my new scythe!) then chicken tractoring to harvest the lush growth and manure the beds all year. The chickens will be moved frequently enough to not kill the mixes until late in the season. Seeing as both the PVO mix and the Sudan Grass are capable of putting on 4 tons of biomass per acre I should have plenty of extra growth for supplemental on site composting to provide compost for our Eco Victory Garden projects. In 2009 these beds will be prepped for the veggie gardens that will rotate over. Beds that will hold early spring crops will be fall planted with a crop that winter kills like Oats. The mirror beds may also be used to grow winter fodder for the chickens by letting some oats go to seed. Making the paradigm shift to the Mirror Beds has completely freed my thinking to move onto other, more practical matters like Chicken Breeds, veggie cultivars, pen design, and problem solving how the heck I plan to grow 1000 transplants without a greenhouse! Expect a flurry of posts on these topics in the coming weeks before I start being forced to spend less time posting and more time doing.

I have already begun meeting with my restaurant clients to get their inputs and commitments. 2008 is shaping up to be a great year! To say that I am stoked for Spring is a huge understatement!

-A very excited Rob

Be the change!!

10 Responses

  1. chicken tractors are going to be a big item, Has anyone put them into mass production yet?

    What would be the procedure for doing chicken tractors in quantity of a dozen at a time,, small labor force to work with…. any and all ideas needed..

    thanks.

    muriel schmidt, 2966 CR 207, Eureka Springs, Ar
    72632- 9469
    phone, 479- 1530 5444

  2. Muriel Schmidt Chicken Tractors have been around for some time now.
    Google Joel Salatin the so called king of the chicken tractor. He has several books out on the topic and does farm raised grass fed beef, free ranged chicken tractor chickens, and more on his farm in Virginia.

  3. We have a whole acre, but are not allowed any coops or livestock.

    Sigh. Hubby won’t move.

  4. Interesting ideas. On the question of tilling and application of animal manures, I tried placing wetted cardboard boxes, from the local supermarket, directly on the soil and then piling the poo onto this. I was using a small site previously leveled for a shed which wasn’t built. The “soil” consisted of sand and yellow clay. I was using goat poo but has since started using rabbit. For the raspberries I used an axe and cut through the bed to plant out. 12 months later when we moved house, I dug up the raspberries and found the sand and clay had been replaced with black, worm filled, humus rich soil. I had, in the 12 months, grown in similar beds, beans, peas, corn, zucchini, squash, broad beans, tomatoes and vetch. After each crop I laid more cardboard and manures. This system worked well. The manures held moisture for six months over winter (We don’t get snowed in) during a particularly nasty drought. In the same way Nature never tills, the microbes and worms will arrive if the conditions for their living are provided. Yield per unit area is about 8 times that of conventional market gardening. I suspect that will increase to a maximum of 12 times over three seasons. The key is to have the poo.

  5. Some parts of the land that are to be tractored could be planted in pearl millet. It gives a quick harvest, chickens love whole sprays of it, and it boosts eggs’ omega-3 content.

    It might be well worth leaving some planks in the beds a few days before the chickens arrive, to serve as insect habitat. They can then be moved to the next location in the days before the tractor moves on, to keep the rate of forage to feed up as plant supplies decline.

    • Two things I forgot:

      I’ve read that biomass production can be great from a hedge. Something like honey locust with an understory of partridge berry would also give chicken feed.

      Second, have you considered using black soldier flies to compost your cuttings? I could imagine a setup that drains excess liquid into the garden bed, and allows larvae to crawl into the tractor. Some of the designs online just use 5 gallon plastic buckets.

  6. Coming back to this after a few days:

    I found a whole series of videos on cover crop systems on Youtube, under the heading “weed ’em and reap.”

    In one of them, a farmer (in Wyoming, I think) mentioned that she saw quack grass die out in favor of mallow (malva neglecta) plants after a few years of growing clover and mowing it frequently.

    In her case, the clover was grown in “paths,” but her paths were wider than the beds, to accommodate equipment.

    I recommend the videos, they’ll give you all kinds of ideas on cover crops!

  7. One more idea, although it’s kind of a crazy one: giant knotweed.

    You only need one plant per square meter, ever. It yields 10 to 30 tons dry biomass per hectare per annum, about one third each leaves, woody stems, and below-ground parts.

    The chickens could conceivably be kept in the understory, so the area occupied by the tractor would still be photosynthesizing.

    You would have to transplant the rhizome bed whenever rotating out of knotweed, and be careful to get the whole network of rhizomes or willing to dig out any volunteers, but it seems very amenable to a slower rotation than once a year, and it could be completely cut back so as not to interfere with a winter rotation like rye/vetch.

    • I forgot to mention: its leaves contain a chemical that prevents powdery mildew, when applied to other plants as a tea. Also the leaves and shoots are an OK fodder.

      This might also be an OK species for the quack barrier, if planted on the north edge of the garden, and/or cut down every month. It’s invasive in stream beds, but seems to need water to the point that it might be dependent on humans in cases like yours.

  8. Chicken tractors are a great idea and my favorite book about this is The Permaculture Home Garden:
    http://www.tropicalpermaculture.com/permaculture-home-garden.html

    It goes through exactly what you need to have a functional and productive chicken tractor system with minimum distance to move the thing and maximum fertility. Highly recommended.

    I wonder if people in areas really prone to foxes etc might do better with an integrated, properly fenced orchard using chickens in a rotational grazing system… but the Permaculture Home Garden still gives you excellent ideas about successional cropping and fertility building.

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