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Are Black Soldier Fly Larvae Good Food for Livestock?

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Are Black Soldier Flies the Ultimate Livestock Feed?

In an era we live in, people are more removed from their food than ever. The practice of factory farming on a large scale has been shown conclusively to be harmful not only to the environment, but to our health. 

Because of this, lots of people are returning to the old way - producing their own food. The joy of growing your own food, even just in a small-scale garden, is immediate. 

Many folks want to take it a step further by practicing animal husbandry. Raising your own chickens, cows, pigs, sheep, goats, or whatever strikes your fancy is a very fulfilling practice. And the benefits are limitless.

But animal husbandry isn’t easy, and it sure isn’t cheap. In particular, animal feed is a costly (and not very sustainable) product that can be a major setback for lots of folks. If only there were a better way to feed livestock that didn’t cost so much, and didn’t consume so many resources in the process! 

Well, we’ve got news. As of 2018, the FDA has approved the use of black soldier fly larvae for livestock feed. But why should you care? Let’s take it from the top. 

The Current State of Livestock Feed

Today, if you wanted to raise livestock, you would go to the supply store and buy a bag of feed. That feed would contain a majority of cereal grains, which consumed a huge amount of water to be raised [https://waterfootprint.org/en/water-footprint/product-water-footprint/water-footprint-crop-and-animal-products/ ]. 

But how much water, exactly? And how much would that feed cost? Let’s break it down by the common kinds of livestock people raise. 


Chicken feed is cheap. For a coop of six or so chickens, you could expect to go through a single large bag of feed a month, costing you around $13. 

But the water expenditure to produce that feed is high. In order to produce a pound of eggs, for example, it takes roughly 1484 liters of water. That’s enough water to fill eight bathtubs all the way to the brim.

While some of that is accounted for in drinking water for the chickens, a majority of it comes from the water required to grow the grains in their feed. 


Cows are much more costly to raise. A single head of cattle goes through roughly 24 pounds in dry weight of hay a day, equating to about a small bale every two days. The average cost for that bale right now is roughly $4.60, totaling $70 per month, per head. 

And the water consumed to produce that feed is outrageous. To produce a single pound of beef, it takes upwards of seven thousand liters of water. So to raise a single cow to slaughter, it would take the equivalent of 2.8 swimming pools worth of water. 

Again, we need to account for drinking water here. But the lion’s share of that water - roughly 99% - is accounted for in water used to grow feed. This also assumes that you’re going to raise the cow for meat and then slaughter it. Which, assuming you’re raising livestock on a small scale, is probably not the case. 

Keeping a cow long-term increases the amount of water consumed by a ton. The amount we listed above for a beef cow taken to slaughter represents just the water consumed in the first two or three years of its life. Which means a cow consumes that much water roughly every three years. 

Any way you slice it, this represents an absolutely insane amount of water. Recent research has shown that the beef industry is one of the leading causes of global climate change, for a number of reasons. This has led researchers to search for alternative feeds and methods of raising cows to reduce greenhouse emissions and water consumed. 


In terms of both cost and water usage, pigs fall somewhere between chickens and cows. Keeping a few pigs will require about a bag of feed each per month, plus whatever kitchen scraps or extras you happen to give them. Expect about $40/mo for two small pigs. 

As far as water goes, a pound of pork costs roughly 2720 liters of water. Because pig feed is mostly corn, water costs are even higher for feed. Like with cows, keeping pigs long term costs even more water. And there are lots of benefits to keeping pigs and not eating them. 

Pigs are incredibly efficient at clearing land for crop rotation. They will root in the earth and completely sterilize it of root systems from the previous season’s crops, effectively turning over the topsoil, aerating it, and mulching it in one go. 

For homesteaders or people looking to scale up their home gardens, having a few pigs is a great idea. They’re fun and full of personality, and super handy to have around. 

Increasing Demand for Water

The most astounding part of this data is that water usage for livestock feed is only expected to increase [https://www.thepoultrysite.com/news/2016/04/how-much-water-does-it-take-to-produce-meat ]. By 2025, the World Wildlife Fund estimates livestock production water usage will increase by 50%. 

Over the last few years, we’ve begun to finally see the effects of global climate change. Each year surpasses the last for high temperatures. Hot places are getting hotter, and wet places are getting wetter. Extreme weather events are increasing. And in much of the US, a permanent state of severe, to extreme, to even exceptional drought [https://droughtmonitor.unl.edu/ ] seems to have set in, with no signs of letting up. 

In the world we now inhabit, every drop counts. It is more essential now than it has ever been that we get closer to our food, and do everything in our power to reduce frivolous water consumption. 

That’s enough doom and gloom for now. Let’s talk about solutions. 

What Are Black Soldier Fly Larvae?

Enter, the black soldier fly. But what is a black soldier fly? By its latin name, Hermetia illucens [https://en.wikipedia.org/wiki/Hermetia_illucens ] is a species of black fly, like the common house fly. But they have a few crucial differences that separate them from normal house flies. 

For example, black soldier flies don’t bite, and they don’t spread disease. They also have a knack for out-competing other common black fly species, replacing your house pests with useful bug friends. 

But what do they do? For starters, they’re incredible composting worms. This is because their guts are fantastically efficient at processing (and disinfecting) detritus of all kinds. Normally, if you were going to start a vermicompost bin, you would be limited to composting only leafy vegetable matter. No meat, no citrus, no dairy. 

But black soldier flies will happily eat and compost all of the above, and more. You can even feed black soldier flies animal waste, and they will turn it into completely safe-to-eat insect protein. And most importantly in the context of environmental sustainability, black soldier fly larvae consume NO water beyond their food. Where it might take hundreds of gallons to produce a single bag of feed made from grains, the same weight in black soldier flies would consume almost no water at all by comparison. This represents a massive difference in water consumed when raising livestock. 

The black soldier fly begins life as a small, oblong grub or larva. We refer to these little guys as black soldier fly larvae (BSFL), or composting grubs. They eat all kinds of biological waste (in our case, kitchen scraps, organic waste, and even animal waste). As they eat, they grow larger and produce “black gold” liquid fertilizer, which you can collect and use in your garden. 

At a certain point in their development, they will be instinctually driven to leave the hot, humid environment they started life in. In search of a cooler, drier climate, they will worm their way out of the compost pile, trying to find a place to pupate into a winged fly, or nymph. 

As they wiggle their way out of the compost, you can collect them and use them as feed. Simple as that. They require a grand total of zero water aside from the water found in their food. You feed them waste of all kinds, they turn it into nutrition for animals and fertilizer for plants. 

Superbugs, Superfood

But are they really all that nutritious? If you’re new to the concept of using insects as feed, it might seem like a strange idea. Part of the issue here is that there is still a lot of research to be done. For example, research has suggested that even strict herbivores like cattle could benefit from BSFL [https://www.wageningenacademic.com/doi/10.3920/JIFF2021.0166  ]. But further research is needed to understand how to make BSFL economical for certain kinds of livestock. 

Black Soldier Fly Larvae Nutritional Content

What we are sure of is their nutritional content. When fed a diet of organic material [https://www.nature.com/articles/s41598-019-46603-z ], BSFL contain roughly 50% protein and 35% fat, with an amino acid content similar to fish meal. They have long been recognized as a healthy alternative feed for not only livestock, but even humans [https://www.sciencedirect.com/science/article/pii/B9780128099131000119 ]. 

It’s also noteworthy that their nutritional content changes based on what they are given as food [https://kimmyfarm.com/en/nutritional-value-of-black-soldier-fly-larvae ]. Food sources like manure produce fattier BSFL, whereas using pure green waste produces much leaner composting grubs. 

FDA Approval

Which bring us to the most recent news, that the FDA has approved BSFL to be used for livestock feed [https://www.prnewswire.com/news-releases/black-soldier-fly-larvae-ingredients-receive-fda-recommendation-for-poultry-diets-300709862.html ]. This decision could have huge impacts on large-scale farms across the country, providing a much greener alternative for feed across the board. 

But it also gives us, the backyard gardeners and would-be homesteaders who want to have a bigger hand in our own food production, some extra assurance. Black soldier fly larvae are safe, nutritious, and green. There is no question about it now. 

Which Animals Can Eat Black Soldier Fly Larvae?

The next question is: which animals can you feed black soldier fly larvae to? The most obvious answer, of course, are omnivorous stock animals like chickens and pigs. Because mealworms are already a common kind of feed used for chickens, switching to BSFL is probably the most natural for them. 

The next most obvious is pigs, who will eat anything (much like black soldier flies). Pigs are hearty omnivores that will love the high protein content offered by black soldier fly larvae, regardless of what kind of other nutritional content they have. Chickens are very similar to pigs in this way. 

Herbivores pose a slightly different challenge. As we mentioned already, more research is needed to fully develop plans for feeding herbivorous stock like cattle BSFL. It’s likely that, in order for BSFL to be nutritious for herbivorous animals, the grubs will need to be fed a particular mixture of compost scraps. 

But then again, we just aren’t sure for now. More experimentation is required to get the exact recipe for success nailed down. What we know for certain is that black soldier flies aren’t harmful to primarily herbivorous stock. 

Circular Agriculture

What black soldier flies accomplish is a step in the right direction. The end goal of moving toward more sustainable farming and food production practices is called circular agriculture

Circular agriculture is a fairly new concept to food science. It means running an operation where nothing goes to waste, and you’re able to produce everything you need to operate your farm right there on your farm. Your byproducts are recycled into feed, which produces food, and so on. 

But how does this relate to the average joe who just wants to do a better job on a small scale? Let’s say, for example, that you have a large square foot garden, a chicken coop, and also home brew beer and cider. 

The byproducts of your operation would include: weeds and inedible plant parts from your garden, chicken manure, and spent grain from brewing. In addition, you will always have a good cross section of kitchen scraps readily available. 

Normally you would need to purchase inorganic fertilizer and feed made of grain at the store to keep your garden and stock going. But by introducing a BSFL compost bin, you can use all of the byproducts, normally “waste,” of your home farm to produce fully organic fertilizer and raise BSFL for feed. Your fertilizer enriches your crops and your composting grubs feed your chickens. And the cycle starts over again. Best of all, you get all the feed you need for free.

With circular agriculture, nothing is wasted, and no toxic byproducts are created. You consume exactly as much water as you need, and nothing more. This method of agriculture is the gold standard for sustainable practices. And if we want to change the world, the perfect way to get started. All you need now are some black soldier fly larvae to get started! 


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