Why This Matters For Your Flock!
Backyard chicken owners want the healthiest chicken feed possible for their flocks. Insects like black soldier fly larvae (BSFL) are a natural supplement, rich in protein, fat, and calcium, but not all BSFL are created equal. All Data is attached at the end of this blog for full transparency.
Concerns about **heavy metals—particularly lead and arsenic—**have been raised in relation to some imported black soldier fly larvae products. Link to PDF
What the Research Shows (Third-Party Data)
A recent peer-reviewed study conducted by Perdue Farms and published in Poultry Science evaluated 21 retail samples of dried black soldier fly larvae between 2023–2024. These samples were sourced from both China and North America, and tested by accredited labs including Eurofins and Cumberland Valley Labs.
Key findings from the study:
- Chinese-sourced BSFL contained, on average, 25x more lead and 8x more arsenic than North American BSFL.
- The highest levels detected reached 4,930 ppb of lead and 2,620 ppb of arsenic in some Chinese samples.
- Nutritionally, Chinese BSFL had lower protein and phosphorus, but higher fat and iron compared to North American BSFL.
- Many imported insect feed products did not meet U.S. labeling requirements or the nutrient levels they claimed on packaging.
The researchers concluded that elevated heavy metal levels in imported BSFL pose risks to both backyard flocks and human health through egg consumption.
GrubTerra’s Independent Lab Results
At GrubTerra, we test our black soldier fly larvae for chickens through independent, accredited labs.
The most recent certificate of analysis (Bio Synergy Laboratories, May 2025) reported the following for our dried BSFL:
- Arsenic: Not Detected (<0.01 mg/kg)
- Lead: Not Detected (<0.01 mg/kg)
- Cadmium: Not Detected (<0.01 mg/kg)
- Mercury: Not Detected (<0.01 mg/kg)
- Nickel: Not Detected (<0.01 mg/kg)
In addition, microbiological safety tests showed:
- No Salmonella
- No yeast/mould growth
This means that GrubTerra BSFL are clean, safe, and free from detectable heavy metals—making them one of the best natural feeds for chickens.
Important Disclaimer
The data from the Perdue study is not produced by GrubTerra—we are sharing it strictly for educational purposes as it comes from independent third-party researchers.
Our own lab results are conducted separately but use industry-standard testing methods, which allow for meaningful comparison:
- Third-party study methods: AOAC-based protocols with detection thresholds of 2.5–10 ppb for heavy metals.
- GrubTerra lab methods: ICP-MS testing with detection thresholds of <0.01 mg/kg (≈10 ppb), effectively the same sensitivity range.
Because both testing approaches use validated methods with similar detection limits, the findings can be directly compared.
This provides clear confirmation that while imported larvae often show elevated heavy metal levels, GrubTerra’s larvae consistently test at non-detectable levels.
Conclusion
Not all black soldier fly larvae for chickens are created equal. While insects remain a fantastic natural supplement for flocks, source and quality matter greatly.
- Independent third-party studies highlight the risks of imported BSFL.
- GrubTerra’s independent testing confirms that our larvae are free from detectable heavy metals.
Cleaner feed means healthier hens, safer eggs, and peace of mind for backyard flock owners.
Learn more on our GrubTerra blog about chicken nutrition and safe insect feed.
🐔 Ready to give your chickens safe, protein-rich, heavy-metal-free BSFL? Check out our 5lb bag of GrubTerra BSFL today.
