I've seen a few queries from folks interested in doing deep litter pig systems. I work at a teaching farm in Senegal, where we have been experimenting with and upscaling deep litter pig systems for over a year now. I thought I'd share some of our findings and pictures of the latest construction. I'll probably break this up over a few days as I sort through photos.
For some background, we've been raising pigs here for about 5 years. At first, they were just in walled pens, then with concrete floors added to keep them from digging out. Of course, the resulting system was unpleasant for both the pigs and the caretakers. Smells, flies, lots of mucking out, and a steep restriction on normal pig behaviors such as rooting.
In looking for an alternative that addressed these problems, we turned to pasture raising pigs. This was in many ways an improvement, but with a 9 month dry season, few pastures can withstand even rotational pig pressure for long. Our hogs were even dropping trees wherever we put water out for a wallow. They did benefit from the freedom and space, but received limited nutrition from within the pasture. On top of that, fencing was a hassle (especially in the rainy season) and larger pigs tended to bully younger ones around food. Pasturing pigs has worked for a lot of people (including me, in PA, USA), but we haven't figured out a way to make it work really well in our context.
I'd first heard of deep litter pigs systems some 5 years ago, but was hesitant to try it here because of the sheer volume of organic matter that is needed. Here in the Sahel, there can sometimes seem to be a real lack of it, even if you'll recuperate it down the road as compost. Would it be worth it for us, and, more importantly, would it seem worth it to students and visitors to our farm?
A short intro to deep litter systems:
Deep litter systems are living systems in which a thick layer of carbon-rich organic matter hosts a thriving microbial community which works to break down solid and liquid wastes from animals as they are produced. Such as system doesn't require regular cleaning out, and has the added benefit of producing high quality, rich compost. If set up right, they are low maintenance and doubly productive systems. They are especially well suited for animals that like to root or scratch, like chickens and pigs, which keep the littler mixed while enjoying their natural habits. This concept can be applied in a number of different ways, and there's no one right way to do it. The goal, though, is to always have a healthy, living litter. On our farm we always say that the litter of your pen should smell like the forest. If it doesn't, there's something that needs adjusting. A lot of what we have learned has come from Korean Natural Farming (KNF), and although we haven't followed any one recipe exactly, we have borrowed heavily from that tradition for the systems you'll see below.
Our first test was 3x3 m. pen. The bottom of the pen is slightly below the surrounding soil surface, and the cinderblock (common locally) walls are built up allowing for a full meter of litter. This is a number I've seen in a few places, including (especially) KNF material.
On top of the wall, we built a roof structure with locally available materials (eucalyptus poles and grass thatch). Attached to this is wire fencing to maximize air flow. This fencing is cemented onto the wall below.
The litter is composed of the following layers (from the bottom up):
1. Large sticks/logs (to keep keep pigs from digging out)
2. Smaller sticks
3, Millet stalks (ag residue)
4. Peanut shells (cheap local ag residue)
Several days before adding the first pigs, we also inoculated this litter with locally cultured Indigenous Microorganisms and Lactic Acid bacteria. You can find recipes for these in any KNF materials.
In the US (from what I understand), a system like this is legally required to have a liner to keep any potential leachate from entering the groundwater. In reality, this is not a real concern, especially in a litter this deep, as long as the litter is kept healthy. In any case, Senegal doesn't have any such restrictions, so we didn't use one.
In addition to the litter area, we included a small (1x2 m.) wallow area. This walled section was simply filled with soil. Because we live in the tropics, a wallow seemed like a must for our pigs. Water is added manually to this about once a day in the dry season. The pigs really enjoy it.
What we learned from test #1:
Too wet can be a problem, at least with this bedding mix. The only breakdown in litter health occured during the rainy season, when a poor thatch job made for a very leaky roof. For several days after heavy rains, both smell and flies appeared, though things returned to a healthy equilibrium soon.
1 meter of bedding thickness seemed overkill, as the pigs never rooted more than perhaps 30 cm.
Pen access was poorly thought out, so moving pigs in, and especially out, proved difficult.
No smell, no flies at all during the dry season, at least at this fairly low stocking rate (compared to similar systems in SE Asia).
The pigs seemed happy and healthy until the day of butchering. They rooted, they wallowed, they searched for lost peanuts and bugs in the bedding.
After the first batch of two pigs, we harvested a significant amount of good compost. After the following single pig finished her time in the pen, we merely topped off the organic matter before adding 2 more pigs.
Test 2: This was/is a slightly upscaled version of the previous pig hut, retrofitted into an existing single-slope roof structure. Advances include a raised walkway for improved access to the pens, slightly larger size, and somewhat reinforced fencing (welded rebar on lower portions). Test #1 uses a water nipple screwed into a 20 L. plastic container, whereas this house has each pen equipped with a water line.
Here we tried several waterer options. In every case, we've always located the water dispenser inside the bathing area, so that spilled water doesn't become a problem. Pigs like to play with water nipples sometimes and make a royal mess, which could be a problem on the living litter. If they make a mess in their bath, well, good for them. Here, we ended up settling on nipples which are attached (at a 90 degree angle) at the end of a swinging hose/pipe. This gives the pigs access to the nipple, but without any resistance. That way, they spill less and don't wreck any piping.
The litter depth stayed the same, as did the general composition of the litter (though we used a lot more small brush and millet stalks, as that's what we had available at the time). On the initial fill, we actually bought several cart-loads of millet stalks off of a neighboring farmer, who was going to burn them in preparation of planting (a common local practice).
The completed mini-barn has 3 pens, each of which has housed as many as two sows with their respective litters of piglets.
This pens here are 100% covered with a non-leaking roof, and the litter has therefore never gotten too wet from rain. I can't recall ever having litter problems here in the year+ of operation. Occasionally, we've topped off the littler with new peanut shells or other dry organic matter. (Which is necessary especially in the first weeks of operation, as the litter always settles quite a lot).
With these first two tests working well, we felt confident enough to start construction on a larger version to house the bulk of our herd. I have a lot more pictures of that process, which I'll post in the coming days.
For the current barn, our aim is to house a good portion of our pig operation. For us, that means at least 40-60 pigs (of various ages), enough to be able to butcher 1-2 a week. KNF recommends a maximum barn width of about 8 meters for good airflow, so that is where we started. The pens, including the mud bath area, are 8 meters long, and we added an extra meter for a walkway on one side, for a total width of 9 meters (plus overhang). Six pens, each 3.5 meters wide, makes 21 meters of length (plus overhang).
We went with a steel I-beams for the posts and rafters , the simplest and cheapest reliable long-lasting roof construction option in our area. The walls are again cinderblock, but this time we only did minimal digging out of soil (mainly just for the wall footers). Additionally, we decreased the overall wall height, shooting this time for a litter depth of 45-55 cm. If your have well-draining soil or are in an area with no risk of flooding, you can sink your entire litter depth into the ground. This makes access into the pens much easier, and might save you in some construction materials (ex. not having to build the roof as high). For us, on flat ground with clay soil and heavy rains, we opted to build up.
The bathing area needs to be large enough to accommodate at least a couple pigs at a time. As you know, pigs don't sweat on most of their bodies, but really benefit from the marvels of evaporative cooling if you can provide a place for them to get wet or, even better, covered in mud. Our pigs spend a decent amount of time laying in this area, so we're glad we didn't skimp on these. On the other hand, you want to maximize your surface area of decomposable bedding, so don't go overboard! We've usually ended up with around 15-20% of our surface area devoted to the mud bath.
For the purlins (?) we used fairly low-gauge angle iron, which we strengthened by welding rebar as shown in the photo below.
Meanwhile, we started filling in the litter. The more of this you can do before the fence goes up, the easier it will be!
Again, we used a base layer of logs. We aimed for wrist-thick or thicker, 1 meter + in length. The idea here is to keep pigs from digging their way out, and to provide a source of carbon to "soak up" any liquid wastes that make it down that far. In our area, few people have an abundant enough source of wood to supply this layer, as deforestation is well advanced. Because our land has been fenced and restored for 15 years, this isn't a problem for us. If it was, it may be possible to get away without this step, depending on how "diggy" your breed of pigs is, and what else you are using for the upper layers of litter.
After the logs, we laid down finer brush, including the smaller branches of all the trees and limbs we cut to establish the first layer.
The roof design is a simplified version of what we've used for our chickens, and what is typical in KNF systems. The idea is to use rising hot air (created by the animals and the decomposing litter) to create a convection current that sucks cool air in from the sides, even when there is no breeze. This is achieved by having a 1 meter wide gap along the eaves of the roof where the hot air can vent. If the building is oriented perpendicular to the prevailing wind direction, this air will be further sucked out by the low pressure system created by the air moving over the roof. We oriented our building East-West on the recommendation of a KNcF instructor. For us, this means that the gap in the roof is at the top end of the south-facing roof slope. Typically, a tarp or other temporary covering will be used to cover this gap during rainy weather. So far, we haven't had to cover it, though that may change as the bedding matures.
As we ran out of already-cut brush for the second layer, we started trimming and thinning live Acacia seyal trees, our dominant pioneer species. At this stage, we should have taken more care to separate out the larger branches, trim them down, and add them to the first layer. Since we included some whole branches in layer 2, some of these branches quickly migrated through the third and fourth layer once the pigs were added. In other words, layers 2-4 should really only include fairly finely chopped (<50 cm long) material, so as to settle well and not to obstruct pigs from rooting or bedding down.
For the third layer we used peanut shells (20-30 cm), an agricultural byproduct available here in abundance. It has a lot of features of what you want in your upper beddling layers: dry, fairly fine, carbon-rich. Wood shavings, sawdust, dry leaves, and chaff are other options... just use whatever is readily available in your area.
Before adding the final layer, we inoculated the peanut shells with fermented rice bran, a form of Indigenous Microorganisms we culture on site.
The final layer is millet hulls (~10-15 cm). At this point, based on our experience with chickens, we lightly watered down the bedding to get the microorganisms started, and then gave them a few days before we added any pigs.
This is great. I would love to adapt something similar here in Kenya, albeit on a smaller scale. Do you ever remove the bedding, or you just keep adding on top? What do you feed the pigs, aside from what they root out of the bedding?
Thanks for the replies and interest. I should say here that we are still very much in the learning and experimenting process, and will no doubt make many more changes before we have this system perfected for our conditions. Hopefully you can learn from and build on our experiences as we go, as we have on that of others.
Miles, let me address you questions first.
The KNF tradition has developed a number of recipes for culturing locally occurring beneficial microbes. The resulting cultures are used in a variety of ways: in livestock feed (to improve gut flora and aid in digestion), on crops (to combat bacterial and fungal attacks, or to trigger certain plant growth responses), and on animal bedding. In this last use, the microbes are used to alter or speed up the decomposition process at work in the bedding. By culturing beneficial microbe X and then applying it onto the bedding, its is hoped that microbe X will become a backbone of the microbial community. This helps to ensure that any animal wastes start breaking down aerobically as soon as they hit the bedding. You may be familliar with EM (effective microorganisms), commercially produced microbial solutions that are marketed for these and similar applications. The recipes used by KNF aim to culture local strains of these same microbes - often referring to them as IMOs (Indigenous Microorganisms) - using commonly available materials.
Now, this is not to say that deep litter couldn't function without these inoculations. We've never not inoculated, so I can't say for sure. The indigenous microbes we are culturing are, assumedly, already present to some degree in the very bedding we are using, assuming we source it locally. Theoretically, then, this system should work without inoculation, assuming all the conditions are ideal. However, the KNF guys who have been doing this for years or decades recommend inoculating not only to start, but also whenever a problem occurs (like smells going south). Though we've never done any standardized tests, we've been happy with the results when we have applied these sprays/mixtures, in terms of kick-starting the kinds of decomposition we are looking for.
The cultures that we have used on our pig system are (recipes in the links):
1. Fermented rice bran (yeasts and white mold). This is similar to I.M.O. 3 in KNF recipes. 2. Lactic acid bacteria spray - LAB 3. Fermented plant juice - FPJ
Lactic acid bacteria spray is especially renowned for speeding up decomposition and turning an anaerobic process into an aerobic one (assuming air is also present).
Maureen: We don't typically harvest compost from the litter during a pig cycle. After one or two cycles, you can start harvesting compost and replacing it with fresh bedding (though this is not required). Otherwise, it's just a matter of adding fresh bedding material as the litter settles, decomposes, or develops a problem (like getting wet!). As far as feed goes... I'll dedicate a post to that on another day. Stay tuned!
With the fencing and gates installed, it's time to add the first test pigs! Some of the big questions with this pen are:
1. What density can be maintained while keeping a healthy litter?
2. How will this thinner bedding fare?
3. How do we best manage pig groups within these larger pens?
For feeders we are using old tires, one rim cut off, and then lined on the bottom with cement, enough to make the tires hard to flip.
We sorted the pigs by size, which is how we plan to keep them. The youngest ones were really showing signs of stress/hunger by the time we got them sorted into the new pens (from being bullied in larger groups), but made a rapid turnaround once settled into the new pens.
This is all very fascinating for me. I have heard tangentially of KNF and the use of bokashi composting, and of Deep Litter Method (particularly in respect to chicken bedding; I use very deep litter in my coop now, although have never tried inoculating it with microorganisms). However, until coming across this thread, I was unfamiliar with combining KNF practices with deep litter in particular, and also unfamiliar with the use of deep litter for pigs. This is good news for me, because I just acquired four feeder pigs a couple days ago! We are now the happy owners of two mulefoots, 6 weeks old, and two 12-week old swallow bellied mangalitsas.
I am really interested in further investigating deep litter for pigs, and will be proactively doing so in the next couple of days. I am in Michigan so preparing for the coming winter; the heat generated by a deep litter system would be particularly useful in my climate! Right now, we have the pigs in pig shed built by the former property owners, it is a wooden structure with a tin roof (not too leaky but needing some repair) on a concrete bed, divided into a couple interior pens with wooden barriers about 1.4 m high. We intend to develop a pasture/forest system for rearing our hogs, but don't have all the infrastructure in place yet. So, for the time being, this concrete bottomed pen is home, for at least the next 6 weeks. I had been so focused on planning for pasture and agroforestry systems for the pigs that I hadn't really concerned myself with management of a more confined space until I got them home on Saturday. I had been assuming I would have to be doing a lot of frequent mucking and straw removal/replacement, and learning that there is an alternative is good news.
Fortunately, we have a large amount of straw and old hay in the barn left behind by the former owners, and have put down a good layer of straw as bedding (although not several feet worth, as your photos would suggest). What I am wondering is if you think the layers of logs/twigs would be necessary on a concrete pad, or if we could simply put down a buttload of straw to get started? I am also wondering about the latrine area in your pens; I imagine that your pigs have a particular poop corner. Do you find it necessary to actively redistribute the feces in your pen? Or do they take care of that for you? Finally, might dried leaves or corn husks/stalks be useful as a layer? If so, where in the mix? We are entering fall here and have both in abundance.
Thanks so much for posting this Noah! I just discovered Korean Natural Farming for pig raising a couple of weeks ago. I was looking for stocking density on pasture. I really like this idea for situations where land is limited.
I'd like to try a partial pasturing method combined with a deep litter barn. This idea comes from managing horses, which is what I have the most experience with. Horses can be turned out for portions of the day and they can be kept in the barn or paddock if the ground is too wet and the risk of damage the grass is high.
If 2 to 4 small pastures surrounded a deep litter barn, I wonder if limiting the pigs turnout time could sufficiently reduce damage to the pasture? Just like the horses, they could be kept in when the soil moisture is too high.
I have 2 red wattle feeder pigs that I've kept in a 40 foot x 40 foot pen. It has a little 8' x 5' shelter off of one corner. The laid the pen bare of the old Bermuda grass blanket within a month or less. The pen has been bare since then. They do have a terrific wallow in the middle of it.
They spend most of their time in the little shelter, but on warmer days they soak in the mud a lot. Regardless of the temperature, I see them bucking and playing once in a while. They are just under a year old and weigh at least 300 lbs. , I think.
I may try a smaller breed this year and also might be able to build a deep litter barn on the edge of the horse pasture, if the landlord allows it. I'm renting on what used to be a goat dairy.
I'm really happy other people are writing about KNF. I was worried that website I found was the only source and that it could accidentally disappear.