Black Soldier Fly Larvae for Chickens: Rearing and Feeding Rates

Why farmers keep asking about larvae

Most farmers we talk to have already done the same sum on the back of an envelope. Feed is the biggest cost on a poultry farm, and protein is the most expensive part of the feed. When soya or fishmeal goes up, the mash goes up with it, sometimes inside a single week. So the question comes round again and again: can I grow some of my own protein?

Black soldier fly larvae are the answer most people try first. The adult fly does not eat and does not bite. The larvae, though, get through kitchen scraps, fruit peel, brewers' grains and other plant waste faster than most people expect, and they turn that waste into a body full of protein and fat that a chicken can use. Done well, that is a neat loop. Done badly, it is a smelly tub of maggots behind the house.

It helps to know which birds you are feeding before you start. Our breed guide sets out how different birds use a ration, and that matters once larvae enter the picture.

What is actually in a larva

Dried whole larvae meal usually lands somewhere around 40 to 50 per cent crude protein in the published analyses we have read. It also carries a lot of fat, sometimes a quarter of the dry matter or more. That is useful energy, but the fat goes rancid if you keep the meal hot and damp. Those numbers are typical, not a promise about the bag in front of you. The rearing feed, the age of the larvae and the way they were dried all move the figures.

Two other things matter more than people expect. Insect shells are made of chitin, which birds digest less well than the protein in soya, so the usable protein is lower than the bag says. The amino acid balance is good on lysine but usually lower on methionine than fishmeal. In practice that means insects do not replace a premix on their own. You still need your amino acids and minerals covered, and a bird fed on insect meal alone will grow badly.

Ash tells you something too. A high ash figure can mean the larvae were reared on dirty substrate, or that sand or soil got into the batch while it was dried. If the ash on the analysis looks high, ask the supplier how the larvae were raised before you buy again.

Fresh larvae or dried meal: which suits your farm

Fresh larvae suit a small, free-range flock that you can feed by hand. You pick them out of the bin in the morning, scatter them on the ground, and the birds go for them at once. A hen chasing a larva is a busy hen, and that activity helps birds that have been cooped up in a hot house. Flocks of Kuroiler or Noiler birds, which forage well, tend to take to larvae quickly. The downside is that fresh larvae spoil quickly in Ghana's heat, and you cannot feed a day's catch to a shed of 500 birds and expect it to keep.

Dried meal suits a farm that mixes its own feed, or buys from a mill that will mix it in. It keeps longer, weighs less, and goes into the ration like any other ingredient. But it needs drying, grinding and proper storage, and it is only as good as the batch you bought. A dried meal that smells faintly of ammonia or has grey patches is telling you the larvae were kept too wet or dried too slowly.

If you can only do one thing this year, start with fresh larvae as a treat and put your effort into learning how the bin behaves. Dried meal can come later, once you know what you are buying and how your birds respond to it.

Rearing them without a smell problem

Adult flies lay their eggs in dry crevices close to the substrate, so the set-up needs a place for them to mate and lay, shade, and room to fly about without flying into your kitchen. A simple enclosure of fine mesh over a frame does the job. Keep it out of direct sun, and stand the bins off bare ground so water does not run underneath them.

The larvae need warmth. They do best in the region of 27 to 30 degrees, and they slow right down on a cold harmattan night. The substrate should be damp, like wrung-out bran or a wet crumble, not swimming. If you squeeze a handful and only a drop comes out, you are about right. A bin that runs wet smells sour, draws more flies, and drowns the youngest larvae.

Watch the smell every morning. A well-kept bin smells like mild, slightly sour waste. If it smells like rotten meat, you have overloaded it with protein-rich waste, the lid is trapping moisture, or something dead has got in. Remove the bad material, dry the top layer and feed the bin less for a few days. Do not try to cover the smell with more waste. That only makes it worse.

Once the larvae are fully grown, they leave the food and crawl up and out of the bin. A simple ramp into a collection tray lets you gather them each day without digging through the feed. This self-harvest step is the reason the system is worth the effort, because it saves you a great deal of labour.

What to feed the larvae

The rule is simple. Feed plant waste that you know is clean. Fruit peel, vegetable trimmings, bread that has not gone mouldy, brewers' grains and the cut ends of greens all work well. The larvae are not fussy about shape, but they are fussy about ingredients that rot badly.

If you already give your flock scraps, the rules in our kitchen scraps and forage guide apply here too. Keep meat, fish, offal and dairy out of the bins. Keep manure out too. Some people do rear larvae on manure, but on a poultry farm you are trying to keep disease away from the flock, and manure carries the very bacteria you are working to avoid. Mouldy grain is also a problem, because the moulds that grow on it can carry aflatoxin into the larvae and then into the meal.

Chop large pieces small. A bin fills with waste far faster than the larvae eat it when the pieces are big. Mix in a little dry bran or sawdust if the waste is very wet, such as melon or overripe fruit, so the substrate stays crumbly. Add waste in thin layers each day rather than tipping in a full day's worth at once.

• Use only plant waste you have seen with your own eyes.
• Leave out meat, fish, dairy, manure and anything mouldy.
• Chop it, spread it, and add waste little and often.

How much to give free-range birds

Fresh larvae are a supplement. They are a treat, a source of protein, and a way to keep a free-range flock busy, but they cannot carry a flock on their own. Think of them as the protein topping on the mash, not the mash itself.

As a starting point, scatter around 100 grams of fresh larvae a day across a flock of 100 free-range birds, in the morning when the birds are hungry, and watch the flock for two weeks. Some birds will gobble them and some will ignore them at first. If the birds leave a lot on the ground, cut the amount. If the strong birds fight over them and the rest get none, scatter them over a wider area or in two places. Good management beats a bigger handful.

Adjust the amount to the birds in front of you. Meat birds and laying hens on a full mash need less, because the mash already supplies the protein they need. Local birds that roam for much of their own feed usually take more. Keep the figure in your head as a rule of thumb, not as a recipe. Farmers who also grow leaves for their flock may want to compare larvae with our moringa and leaf meal guide, since the two suit different parts of the ration.

Putting dried meal into the mash, step by step

When you are ready to use dried meal, do not tip a bag into the mixer and hope. Work through the steps below, one batch at a time.

1. Get the written analysis for the meal, and write the protein, fat, moisture and ash figures on your batch card.
2. Check the protein of the soya or fishmeal you already use, so you can compare cost per kilo of protein rather than cost per bag.
3. Start with a small share in the grower or finisher mash, usually a few per cent of the ration, and replace part of the protein ingredient rather than adding on top.
4. Mix for longer than you think. Uneven mixing shows up as birds that look different from one pen to the next.
5. Weigh the feed you put in and the feed left at the end of each week, so you can see whether the birds are eating it.
6. After two weeks, weigh a sample of birds against a pen on the old mash. If the new mash is holding growth and feed use, you can move up a little. If not, go back.

Most published poultry trials put dried larvae meal somewhere between a few per cent and about a tenth of the diet, and the results depend heavily on the bird, its age, and what the meal replaces. Treat those trials as the outer limit for experimenting, not as a target to hit on day one. If you want the full picture of how a mash is built, our feed formulation basics walks through each ingredient group.

Working out whether meal is worth the money

The decision rule is simple, and it is the one we use for every protein ingredient we look at. Divide the price of a kilo of the ingredient by its protein percentage, then multiply by 100. That gives you the cost of one kilo of protein. Buy whichever protein source gives the lowest number, once you have allowed for how well the birds use it.

Here is an illustration with made-up prices, so the arithmetic stays visible. Say a dried larvae meal at 40 per cent protein costs GH₵20 a kilo. That works out at GH₵50 for each kilo of protein. A soya cake at 44 per cent protein costing GH₵16 a kilo works out at about GH₵36 for each kilo of protein. On those figures soya is cheaper, even though the larvae are not a bad product. Change the prices and the answer changes too, which is exactly why you should run the sum with your own quotes every time.

The sum also leaves out the labour of rearing, the bins, the mesh, the power for drying, and the cost of spoilage. A farm that rears its own larvae on waste it already produces may come out ahead on protein. A farm that has to buy waste, dry it and carry it to the bins often does not. For the wider picture on stretching a feed budget, our cheaper feed alternatives guide compares the options side by side.

A worked example for a small free-range flock

Take a farm with 120 birds on free range that also eats a shed mash in the mornings. The farmer keeps two bins going, each with about 15 kilograms of waste in it at any time. Once the larvae reach harvest size, the bins give roughly 2 kilograms of fresh larvae a week. That is not a huge amount, but it is protein from waste that would otherwise have gone on the compost heap or into the rubbish fire.

Spread across 120 birds, that is about 17 grams of fresh larvae per bird per week. Scatter it in small daily amounts and the birds get a steady treat without the mash changing at all. The flock still eats its usual mash, and the larvae are an extra. The farmer does not cut the mash, because the birds still need the energy and vitamins the larvae do not supply.

Now suppose the same farmer wanted to put dried meal into a 300-kilogram mash batch at 5 per cent. That is 15 kilograms of meal, which is far more than two bins give in a week, even after drying. The honest answer is that a small farm will use its larvae as a treat, and buy meal in bulk if it wants protein in the mash. Our feed intake guide helps you work out how much mash a flock of your size really needs, which is the number to start from. If you are planning a free-range flock from chicks, you can order through our order form, or message us on WhatsApp at +233 24 915 1503 before you commit.

Mistakes that cost more than the larvae save

The first mistake is starting too big. A farmer who sets up twenty bins before he has learned how one bin behaves ends up with twenty smelly problems. Start with two bins, learn them, then add more.

The second is feeding the wrong waste. Meat scraps and fish heads make the bin rot and draw the wrong flies, and they put disease risk right next to the flock. We would rather a farmer kept the bins small and clean than fed them everything from the kitchen bin.

The third is buying meal without an analysis. A bag with no protein figure on it is a bag you cannot price, so you cannot tell whether it beats soya. Ask for the numbers before the money changes hands.

The fourth is storing dried meal like ordinary feed. The fat in larvae meal goes rancid faster than soya cake, especially in a warm store. Keep it sealed, cool, off the floor, and used within a sensible time. Smell it each week. Rancid fat smells like old crisps or paint, and birds will refuse it.

The fifth is expecting insects to fix everything. A flock with coccidiosis, worms or a bad water supply does not get better because the larvae are fresh. Sick birds need a vet, and your vet's advice comes before any change to the feed.

Before you start: a short checklist

Work through this list before you spend money on bins, mesh or a dryer. If you cannot tick most of it, start smaller.

• You know which plant waste you will use, and where it comes from each day.
• You have shade, a dry place for the bins, and mesh to keep flies inside the enclosure.
• You can check each bin morning and evening for moisture and smell.
• You have a tray or ramp to collect the mature larvae each day.
• You have asked for an analysis for any meal you plan to buy.
• You have worked out the cost per kilo of protein against your current soya or fishmeal.
• You will change one thing at a time and write it on the batch record.

Once the checklist is done, the next useful step is to read about the protein sources you already use, so you have something solid to compare the larvae against.

Questions farmers ask