How many soldier fly larvae for your chickens?

How we calculate

• Larvae per day = number of hens × larvae per hen, rounded. Weight ≈ 0.18 g per larva, so 9 g for 50 larvae.
• Waste (kg / week) = larvae per week × 1.5 g ÷ 1,000, rounded to 0.1 kg. If you enter your waste, the maximum possible = waste × 1,000 ÷ 1.5 ÷ 7 larvae per day.
• Heat factor = 1 from 24 to 32 °C, 1.2 above 32 °C, 1.5 from 20 to 24 °C, 1.8 from 18 to 20 °C. Below 18 °C, growth stops.
• Larvae in the bins at once = larvae per week × 2 weeks × factor. 60 × 40 cm bins = that number ÷ 3 larvae per cm² ÷ 2,400 cm², rounded up, at least 1.
• Prepupae to keep = 4% of the week’s larvae, rounded up, at least 30.
• First harvest = 4 weeks × factor, rounded.

Example

10 hens, 50 larvae per hen per day, at 22 °C. Larvae = 500 per day (≈ 90 g), so 3,500 per week. Waste = 3,500 × 1.5 g = ≈ 5.3 kg / week. At 22 °C the factor is 1.5: 3,500 × 2 × 1.5 = 10,500 larvae at once, so 2 bins of 60 × 40 cm. Prepupae: 140 per week. First harvest: 4 × 1.5 = ≈ 6 weeks.

Sources: Eawag – Black Soldier Fly Biowaste Processing, common keeping practice. These are guidelines: real output depends on heat, humidity and the waste.

Frequently asked questions

How many larvae should I give a hen?

About 50 larvae (9 g) per hen per day, on top of layer feed. They do not replace it.

How much waste do I need?

One larva eats about 1.5 g of fresh waste while it grows. For 5 hens at 50 larvae a day, plan on about 2.6 kg a week.

What temperature do the larvae need?

Ideally 25–30 °C. Below 24 °C they grow more slowly, and below 18 °C they almost stop.

Can I use my kitchen scraps?

Better to use raw plant matter that never went through the kitchen (garden produce, windfall fruit). EU rules ban feeding farmed animals with kitchen waste.