A self-harvesting Black Soldier Fly (BSF) unit is a simple system that allows mature larvae to crawl out of the feeding container and drop into a collection bucket automatically. This makes harvesting easy and hygienic.

For poultry farmers, this system is very practical because it:

• Reduces labour
• Produces high-protein chicken feed
• Converts kitchen and farm waste into valuable feed
• Can operate continuously

With basic materials available in rural Kenya, you can build one for under KSh 2,000–3,000.

How a Self-Harvesting BSF Unit Works

8When BSF larvae are fully grown (prepupal stage), they naturally crawl away from the food to find a dry place to pupate.

A self-harvesting unit uses sloped ramps so the larvae:

1. Crawl up the ramp
2. Enter a small outlet pipe
3. Drop into a collection container

This means the larvae harvest themselves automatically.

Materials Needed

Most materials are cheap and easy to find.

You will need:

• Plastic drum (60–100 litres) or large bucket
• Two small PVC pipes (2–3 inches diameter)
• Small plastic bucket (collection container)
• Wooden or plastic ramps
• Drill or knife
• Wire mesh or net
• Bricks or wooden stand

Optional but useful:

• Roof or shade cover
• Drainage tap

Step-by-Step SOP for Building a Self-Harvesting BSF Unit

Step 1: Prepare the Main Container

Use a plastic drum or large bucket.

Ideal size:

• 60–100 litres capacity

Cut the top open if necessary.

Drill small drainage holes at the bottom to prevent water accumulation.

Too much moisture can slow larvae growth.

Step 2: Create the Larvae Exit Holes

Drill two holes on opposite sides near the upper edge of the container.

Hole size:

• About 5–7 cm diameter

These holes will allow mature larvae to exit.

Step 3: Install the Ramps

7Inside the container, install two slanted ramps leading toward the exit holes.

The ramps can be made from:

• Wood pieces
• Plastic sheets
• Metal strips

Important tips:

• Slope angle about 30–40 degrees
• Surface should be slightly rough so larvae can climb

The ramps guide the larvae to the exit holes.

Step 4: Install Exit Pipes

Insert short PVC pipes into the exit holes.

Angle them slightly downward.

These pipes act as larvae channels directing them into the collection container.

Step 5: Place the Collection Bucket

Place a small bucket or container under the pipe outlet.

When larvae crawl out, they fall directly into this bucket.

This bucket becomes your automatic harvesting point.

Step 6: Add Waste Feed

Place organic waste inside the bin such as:

• Fruit peels
• Vegetable waste
• Leftover food
• Chicken manure
• Market waste

Fill only about half the container to allow airflow.

Step 7: Attract Black Soldier Flies

Leave the lid slightly open or cover with mesh.

This allows adult flies to:

• Enter
• Lay eggs near the waste

Within a few days, larvae will hatch and begin feeding.

Operating the BSF Unit

Once the system is active:

1. Add fresh organic waste daily
2. Maintain moisture (not too wet)
3. Keep the unit under shade

After 10–14 days, mature larvae will start self-harvesting.

They will crawl up the ramps and fall into the collection bucket.

Feeding BSF Larvae to Chickens

BSF larvae can be fed:

• Fresh
• Dried
• Mixed with chicken feed

Recommended feeding rate:

• 10–20 grams per chicken per day

They are excellent protein supplements for layers and broilers.

Production Potential

A well-managed self-harvesting BSF unit can produce:

• 1–3 kg larvae per day

This can supplement feed for:

• 100–200 chickens

Larger farms simply build multiple BSF bins.

Tips for Higher BSF Production

To maximize larvae output:

• Keep the bin in warm shade
• Add waste regularly
• Avoid flooding the waste
• Add small amounts of chicken manure to boost growth
• Stir waste occasionally

Common Problems and Solutions

Bad smell

Cause: Too much wet waste

Solution: Add dry materials like sawdust or leaves

Few larvae produced

Cause: Flies not laying eggs

Solution: Place the bin near animal manure or market waste

Ant invasion

Cause: Sweet food waste

Solution: Place container legs in water trays

Cost Estimate (Kenya)

Typical DIY unit cost:

Total estimated cost:

KSh 1,300 – 1,800

Final Thoughts

A self-harvesting BSF unit is one of the most practical technologies for reducing poultry feed costs. It converts waste into high-protein feed while requiring very little labour.

Many farmers combine BSF larvae, Azolla, termites, and homemade feed to cut poultry feed expenses by 30–50%.For poultry farmers looking to increase profits, BSF production can be a powerful low-cost solution.