By Alice Percy
Copyright ©2006 by the author
Walk into the meat department of any natural foods store, and you’ll likely find organic beef and chicken, but rarely organic pork. Why? The conventional hog farmer – the guy with thousands of sows out in Iowa – uses some of the most noxious "agricultural" techniques. He keeps hogs tightly confined in a highly artificial environment, includes subtherapeutic doses of antibiotics in their daily ration, and often washes their manure and refeeds it to them to save on feed costs. The result is pale, flabby, fatless and flavorless. Who wants to eat that?
The skeleton of the pig tractor consists of 2x6 rough hemlock, 2 feet on center, with the back wall connecting the two skids. Photos by the author.
Maybe the organic pig doesn’t enjoy the popularity of his avian and bovine counterparts because organic farmers have not figured out how to incorporate him into their idea of an attractive, sustainable farm. Hogs require a tremendous amount of feed, most of which is probably imported from off the farm. A few farmers have tried to pasture hogs the way they would a grass-fed beef critter, and have soon discovered that grass does little to assuage a hog’s ravenous appetite, and that hogs are mud-making machines who quickly destroy even a generous parcel of pasture. Some have tried to turn pigs into cows by putting rings in their noses, forcing them to graze instead of root, but many organic certifying agencies prohibit this practice (rightly, in my opinion) as inhumane mutilation.
We organic farmers are supposed to be working with, not against, the forces of nature. We shouldn’t be asking, "How can I make the pig conform to my idea of Salatin-style pasture-based livestock farming?" but "How can I turn the rooting behavior and the gluttony of the pig to my farm’s advantage?" The answer to the latter question is the pig tractor, which uses the pig to plow and fertilize your garden.
Most people interested in organic livestock are familiar with the chicken tractor. The pig tractor is the same basic concept made much sturdier and used a little differently. We build our pig tractors out of 2x6 rough hemlock. The entire structure is 8 feet wide on 16-foot-long skids. One half is an 8x8 shed, 4 feet high in back, 5 feet high in front and covered with a corrugated metal roof; the other half is an 8x8 open yard. The whole thing is fenced with three 16-foot sections of cattle paneling. The removable end panel is held on with four bolts. A sturdy cable is attached to the back corners of the shed for pulling the tractor, which must be made from strong materials and braced thoroughly to withstand a lot of abuse. We usually stock one of these tractors with four feeder pigs or two broodsows. You can also keep eight weaned piglets in it and split them into two tractors before they get too heavy to lift over the fence.
How to Use a Pig Tractor
The pig tractor may be moved with a small four-wheel drive truck or tractor or by a sturdy team of horses who don’t mind having a building following them. To avoid damage, move your pig tractor slowly and steadily, especially around corners. Place it at the beginning of the patch you want plowed and drop four six- to eight-week-old pigs into it. They will run around it several times and then dive into the soil up to their ears, eating leaves, roots and grubs and emitting charming grunts and squeals that will make you wonder how you ever lived without pigs.
Generally, the pig tractor should be moved about once a week; by this time the ground will be thoroughly tilled and the tractor will have accumulated a fair amount of mud and manure. In certain situations you may have to move the tractor more often. Enterprising pigs may begin tunneling under the skids in search of more goodies, and unless the tractor is moved in time, they will eventually emerge on the other side to wreak havoc on your neighbor’s vegetable garden and drive your dog crazy. Heavy rains may flood the pens, as the skids will sink into saturated soil and prevent water from escaping. In this situation you are better off if you have horses to do the moving job, because trucks and even tractors will get stuck in the mud trying to haul the heavy structure. During an extended rainy period, try to move the pens onto a slight hillside (with the shed uphill) so that most of the water can drain off. If you have lots of ground available and would like as much of it tilled as possible, you may wish to move the pen every three or four days.
Moving the tractor is best done with two people – one to do the actual moving and the other to watch the pigs. The pigs quickly learn to walk along with the tractor as it moves, but the first few times they may linger at the back end and risk getting a leg run over. Once, when moving a tractor by myself, the end gate was not securely fastened and the bottom came off, allowing a 500-pound sow to escape. Having a helper can prevent these problems.
As soon as possible after moving the tractor, do something to the tilled land to preserve the nutrients and keep weeds at bay. Depending on the time of year and your goal for the land, this may mean planting a vegetable patch, broadcasting a cover crop, covering with mulch, or some combination of these. We usually transplant tomato or squash seedlings or broadcast buckwheat seed.
A finished pig tractor parked for the winter and housing for four-month-old pigs. (That's Flopsy peeking out from the shed.) Note the multiple diagonal braces, which keep everything in place when the tractor is being moved.
We send our pigs to slaughter at the age of six months, when they usually dress out between 200 and 225 pounds. This means that we keep them for a total of 16 weeks; so, if we move the tractors once a week, we need 16 plots of land measuring 8 by 16 feet that lie more or less in a line. (A pig tractor does not have a tight turning radius.) When the slaughter date arrives, back your trailer up to the end of the pig tractor, remove the end panel, drop the trailer gate, block the gaps with whatever comes to hand (large sorting panels, scraps of cattle panel, large groups of people, etc.) and lure the pigs onto the trailer with a bucket of feed. Good tame pigs usually walk onto the trailer without encouragement, just to investigate the new area. A recalcitrant pig may be moved easily by putting a bucket over its head and using the handle to back it onto the trailer, steering the pig gently by the tail. Put some slop in the bottom of the bucket, and he probably won’t object much.
Pig Tractors in Winter
The worst time to keep pigs in Maine is not during January blizzards, but in November, which often brings torrential rains and cold temperatures when the pigs are still accustomed to the relatively balmy weather of early fall.
If you can keep the sheds dry (in adverse weather it is often a losing battle to keep the outside pen from turning into a small lake), the pigs won’t care how cold it is despite their almost hairless skin. Although pigs are fairly warm-blooded compared with cattle or horses, a good sturdy farm pig (unlike his "hothouse" Iowan cousins) will have about an inch of fat on him, which serves as excellent insulation. Just before the ground freezes, park the tractor on a mild slope with the shed on the uphill end. If possible, face the shed opening to the south. If it must face north, securely fasten a windbreak of plywood across three-quarters of the shed opening. Make sure you like the tractor’s location, because the skids will eventually freeze into the ground. The hogs will dig a "pig pit" in their shed, a bowl-shaped depression in the ground just big enough for the whole group to pile into cozily. This alone can keep them so warm that when they get out of bed on a January morning the pit will steam and be warm to the touch.
The key to keeping pigs in winter is bedding, and lots of it. Enough bedding to line their pit will keep the pigs off the damp, cold ground. The best bedding option is waste hay – it is soft and absorbent, it will add valuable organic matter to your soil, and pigs consider even the nastiest hay edible, so you can keep your pigs "grass-fed" through the winter. How much you need varies widely – we have had some pigs who would barely eat a bale in a week, but the two sows we have now will eat two bales of hay in one night if you give it to them. You can also use wood shavings, but you usually have to pay for them and we have had some hogs suffer skin irritation from lying on shavings all the time. Other options that we have not tried are corn stalks, dead leaves and shredded newspaper. Be imaginative – anything dry and comfortable to lie on that you don’t mind adding to your soil is fair game.
Three-month-old barrows (Rorschach, Freckles, and Dumbo) dive into a fresh patch of pasture in June.
Pig Tractors in Summer
Summer is great for raising pigs, because rain is relatively infrequent, and the variety of foodstuffs can’t be beat. The main problem is keeping the pigs cool. If possible, don’t position the shed opening to face south, or it will be difficult for the hogs to find shade. The plywood windbreak mentioned above can also cast shade in the summer. Pigs usually don’t need any bedding in the summer, unless it’s used to keep them dry during unusually heavy rains; they prefer to lie in cool soil.
The other problem in the summer is water. In the winter we prefer low, sturdy Rubbermaid tubs, because you can beat the ice out of them, but a pig presented with a bowlful of water in July will immediately turn it over on his own head, and 15 minutes later, he’s thirsty. This is because, despite expressions about "sweating like a pig," pigs actually can’t sweat and their best way to cool off is to wallow. The easiest way to ensure that your pigs have drinking water is to hang a 5-gallon bucket on the outside of the shed and run a hose down from it to a low-pressure "nipple drinker," which can be purchased for $3 from a farm supply catalog. If you do this, however, be sure to generously hose down an area inside the pen for the pigs to use as a wallow, or they may overheat dangerously.
Under many management systems, summer brings strong odors and flies to the hog farm. The pig tractor significantly reduces both problems, because the animals are moved frequently, and their manure is covered behind them with mulch or plant growth.
Pig Tractors and Management
In many ways the tractor system makes it easier to manage your hogs well, mostly because it allows you to segregate small groups. When feeding large groups of hogs in one space, piglets that start out small tend to drop further and further behind, because they cannot compete for space at the troughs. When sorting a litter into tractors, you can divide them into small groups of roughly the same size. Feeding pigs in small groups also simplifies tailoring their rations.
Even with a large herd, you can track individual pigs for health records or inspection purposes without the hassle and expense of a tattooer. Paint a number on each pen and record distinguishing characteristics for its inhabitants. Our organic inspector doesn’t have much trouble finding, for example, the all-white male with lop ears in Pen 5, or the female in Pen 3 with the black spot under her left ear.
We are big believers in tame pigs. They are safer to work with, easier to load, and tend to stay calmer at the slaughterhouse, because they are not afraid of humans. The tractor system is better for taming pigs than an open-range system, because the smaller quarters get them used to being handled. Also, for some reason, small groups of pigs become accustomed to human contact more easily than large groups. Spend time making friends with your pigs at feeding time – get into the pen to give them their food, push them around a bit, scratch their itches, give them treats. It will make your life easier on loading day; it will make farming more fun; and I honestly believe it will make your pork taste better.
Pig Tractors and Water Quality
If you were to put one pig on a whole acre of grass and put a ring in its nose, it would still be carrying 250 pounds of pork around on four pointy trotters, and it would rip up the soil around its shelter and its feeding area. No matter what you do, hogs make mud, mud makes runoff, and runoff carries undesirable nutrients into the closest body of water. This is what happens when you mess with nature; the question is how to minimize it.
The advantage of the pig tractor over open-range pasture is that while the degree of disturbance is greater, the area involved is much smaller – it only takes about 1/20th acre to raise four hogs from weaning to market weight. And the degree of disturbance is no greater than if you had taken out your tractor or your team and plowed, disked and spread a heavy dose of fertilizer on the same patch of ground.
Therefore the same environmental precautions apply to pig tractoring as to normal tillage. Never put a pig tractor on a steep slope. Locate tractors at least 100 feet from bodies of water, more if there is a steep slope or no good buffer strip. Plant right after "plowing." If you’re not going to plant a market crop directly behind the pig tractor, broadcast buckwheat seed for a nutrient catch crop. If it’s too early or late even to plant winter rye, then spread mulch to keep the sediment from moving.
Pig Tractors and Pork Quality
Pigs raised inside and fed nothing but corn result in bland and flabby pork. Pigs that are raised on the open range and forage extensively for their food grow slowly and can turn out tough. The tractor system hits a happy medium. The hogs have room to run, play and root, but not so much that they burn too many calories and get tough. Their diet is still grain-based, so they grow out quickly, but because they have access to grass, grubs and roots (and ideally to scraps from your vegetable garden), the meat has that good, old-fashioned pork flavor.
The foreground shows pig-tilled land. The strip of grass was located under the brace separating the shed from the outdoor pen. The background shows mechanicallly tilled land with a fresh crop of weeds already appearing.
Pig Tractors and Your Garden
This is the real advantage of the pig tractor: Your garden reaps the benefits of the hogs’ rooting behavior and their gluttonous appetites. Hogs may be slower at plowing than tractors or horses, but they do a much more thorough job, because they don’t simply turn under and rip up sod; they eat it. They eat crabgrass roots, morning-glory roots or seedheads from thistles. They tromp freshly germinating weed seeds and uproot small trees. They find stones up to 8 inches underground and bring them to the surface to play with. Unlike a tractor – and unlike a moldboard plow drawn by tractor or horses – pigs don’t compact the soil at all. The resulting ground is perfectly open and weed-free. The pigs will not leave things smooth and fluffy; their soil preparation is quite sufficient for transplants or larger seeds, such as buckwheat or corn, but planting carrots will probably require additional, mechanical tillage.
Some people tout the benefits of planting winter rye for eliminating weed competition because of its allelopathic effects. The problem with rye is that its allelopathic effects extend to your crop seeds – you can’t plant for three weeks after tilling in the rye, at which point weed seeds can also germinate. But you can plant directly behind a pig tractor. Your crop seeds will be the first ones in this "sterilized" ground. Also, the pigs will fertilize your garden while they plow. This is where the gluttony comes in.
A hog that gets some exercise will eat about half a ton of grain between weaning and slaughter. The feed bills will make you weep – especially if you’re buying organic grain, which usually costs more than twice as much as conventional feed (we pay over $400 a ton). However, when a hog goes to market, he carries with him only about half the nitrogen and other plant nutrients that he consumed in that time – the rest he left on your garden as manure and urine. So the diversified farmer can be consoled knowing that he has two chances to make money off that feed investment – first by selling pork, and second by selling produce from his well-fertilized garden. Incidentally, the manure application rate resulting from the tractor method presented here is so high that you should plant as intensively as possible, so you should be able to get more produce than usual from the same amount of garden space.
If you want to grow prize tomatoes or lots of heavy feeders such as pumpkins and squash, try planting where a pig tractor spent the winter. This area will have multiple layers of manure, wasted feed and rotted bedding that your plants will love. Last summer my cherry tomatoes grew 7-foot-long vines.
About the author: Alice Percy and her husband, Rufus, farm Treble Ridge Farm in Whitefield, Maine. She also chairs MOFGA’s Public Policy Committee and covers meetings of the Maine Board of Pesticides Control for The Maine Organic Farmer & Gardener.
Is Pig Manure Safe to Use?
Because pigs can carry pathogens and parasites that can infect humans, some Cooperative Extension bulletins recommend not using the manure where crops for humans are to be grown. Diane Schivera, MOFGA’s animal science specialist, suggests having fecal tests done on pigs a few times during the year. If the pigs don’t have parasites (such as worms) that can infect people, then gardening where a pig tractor was previously in place should be fine, although she recommends growing crops that don’t contact the soil, such as sweet corn. Schivera says that parasitic worms tend to be most active during a full moon, so that’s a good time to test. Update, April 9, 2014: New research shows that roundworm eggs can live in the soil for four years, so testing your animals is critical!
Alice Percy believes that any risk is far outbalanced by the advantages of the symbiotic relationship between pigs and garden, being able to grow vegetables and meat on the same ground (potentially very important for small landholders), and the ease of maintaining a high level of nutrients and organic matter in the soil without lots of time-consuming manure and weed management.
Alternating pig pasture with garden space (so that you don't start planting until the year after the pigs were on the pasture) should reduce the risk from pathogens to nil, she believes.
The most conservative option, adds Percy, would be to use the pig-tractored areas to grow food for the pigs only, such as to replant pasture crops behind them (e.g., an oat and pea mix).
Eric Sideman, MOFGA’s director of technical services, reminds growers that using a pig tractor is the same as adding manure to cropland, so a certified grower must meet the waiting period in the National Organic Program Standards. There is a 120-day waiting period between the last day the pigs are on the land and the harvest of the crop (90 days for crops in which the edible portion does not contact soil or soil particles, e.g., corn).