Scattered Insects Boost Broiler Welfare Without Hurting Growth, Study Finds

On a commercial broiler farm, the daily rhythm is familiar: eat, drink, sit, grow. Modern meat birds reach market weight in just a few weeks, but their rapid growth often comes at a cost. Legs struggle to keep up with body mass, breast blisters and skin lesions appear where birds sit too long, and natural behaviours like foraging and dustbathing almost disappear under the pressure of efficiency.

A new study from Nottingham Trent University suggests one deceptively simple change could help: scattering insect larvae directly on the litter, instead of putting them neatly in a feed trough.

The research, carried out in partnership with agri-tech insect company Flybox and published in Applied Animal Behaviour Science, shows that fast-growing broilers become more active and more natural in their behaviour when they have to hunt for dead black soldier fly larvae (BSFL) on the floor – and crucially, their growth and gut development do not suffer.

Why Broiler Activity – Or The Lack Of It – Matters

Modern broiler strains have been selectively bred for:

• Very rapid growth.
• High meat yield.
• Excellent feed conversion efficiency.

This genetic success story has helped make chicken one of the world’s most affordable animal proteins. But it has also brought side effects.

As birds grow heavier, their natural inclination to walk, forage, and play declines. Inactivity is linked to:

• Poor leg health – lameness, joint problems, pain.
• Skin lesions – contact dermatitis on breast and hocks.
• Reduced expression of natural behaviours like scratching, pecking, dustbathing, and exploring.

These welfare problems aren’t just ethical concerns; they carry an economic price in the form of downgrades, condemnations, and treatment costs.

FFA Explainer:

Welfare scientists often use “activity” and “natural behaviours” as practical indicators of how well an animal is coping with its environment. In broilers, more gentle movement and foraging, without harming growth, is generally seen as positive for both welfare and long-term health.

Regulators, retailers, and consumers are increasingly pushing farms to show that birds can move and behave more naturally – but any solution must also keep feed efficiency and weight gain on track.

What Did The Nottingham Study Test?

The research team, working with Flybox, set out to answer a focused question: can we stimulate activity and natural behaviour in broilers without sacrificing growth or gut development?

The design compared two key variables:

• Bird type – fast-growing versus slower-growing broiler strains.
• Feeding method for dead black soldier fly larvae:
• Offered in the trough (standard feeding method), or
• Scattered onto the litter surface, requiring birds to forage.

BSFL were chosen for several reasons:

• They are rich in high-quality protein and fat.
• They are a natural food for birds in the wild.
• They are highly palatable and engaging for poultry.
• They are already being explored as a sustainable alternative protein in poultry diets as part of circular agriculture.

The researchers monitored:

• Active behaviours – running, walking, preening, stretching, dustbathing.
• Foraging behaviour – ground pecking and searching.
• Growth performance – body weight, feed conversion.
• Gut development – a key driver of growth and overall health.

What Happened When Larvae Were Scattered?

The results for fast-growing broilers were striking.

When BSFL were scattered on the litter instead of fed in the trough, the researchers observed:

• An increase of more than 11% in total active behaviours, including running, walking, preening, stretching, and dustbathing.
• A jump of around 32% in foraging behaviour compared to birds given larvae in the trough.

In other words, simply changing where the larvae were placed nudged fast-growing birds to act more like their ancestors – scratching and searching the litter for tasty morsels.

Lead doctoral researcher Chris Onuoha, from Nottingham Trent University’s School of Animal, Rural and Environmental Sciences, explained the mechanism:

“Scattering larvae onto the litter required birds to actively forage to consume them, thereby engaging natural ground-pecking behavior and increased activity,” he said.

Crucially, this extra movement and behavioural richness did not come at the cost of production.

The study found no negative effect on growth performance or gut development in the fast-growing strain. The enrichment added interest and exercise without diluting the birds’ ability to put on weight efficiently.

“The results demonstrate that even birds selected for rapid growth can be behaviorally stimulated without negative physiological consequences,” Onuoha noted. “Increased activity has the potential to improve health and welfare outcomes, particularly in fast-growing birds, with further research needed to confirm long-term health benefits.”

What About Slower-Growing Broilers?

In slower-growing broiler strains – which are already more active and generally considered more welfare-friendly but less economically efficient – the story was different.

For these birds, there was no significant difference in overall activity or foraging behaviour whether larvae were scattered or offered in the trough.

This suggests that:

• Slower-growing birds may already be expressing a higher baseline of natural behaviour.
• The added “challenge” of finding scattered larvae doesn’t change their activity profile as dramatically as it does for fast-growing birds.

From a commercial perspective, the main welfare and economic gains may therefore be in conventional, fast-growing flocks, where inactivity is most pronounced and leg and skin issues cost the most.

Why Black Soldier Fly Larvae Fit The Sustainability Puzzle

Beyond welfare, the study slots into a wider shift in poultry nutrition and farm systems.

The sector is actively looking for alternative protein sources that:

• Reduce reliance on fishmeal and imported soy.
• Cut the environmental footprint of feed.
• Fit into circular agriculture models, recycling organic waste streams.

BSFL tick many of these boxes:

• They can be reared on organic by-products, turning waste into feed.
• They have a favourable nutrient profile for poultry.
• They are naturally attractive and behaviourally engaging for chickens.

Professor Emily Burton, of Nottingham Trent University’s School of Animal, Rural and Environmental Sciences, framed the work this way:

“This work sits at the convergence of welfare science, animal nutrition, sustainability, and commercial practicality.

“By stimulating natural foraging behavior without negatively affecting growth or development, this approach provides a feasible on-farm tool to mitigate some welfare concerns associated with inactivity in intensive production systems.”

From Flybox’s perspective, there is also a business case in scaling insect delivery systems for commercial farms.

Thomas Stringer, CFO at Flybox, said: “Chickens are natural foragers. By supplying insects in a scalable, biosecure way, we enable producers to enhance welfare with minimal disruption.”

A Zimbabwe Anchor: What Could This Look Like In Our Sheds?

For a Zimbabwean broiler farmer in Glendale or Bulawayo, the idea of scattering imported BSFL might sound far-off. Yet the principles from this study can travel.

Across the region, small agri-tech start-ups are experimenting with on-farm black soldier fly production using market waste or abattoir by-products. In many cases, the larvae are simply mixed into feed or fed to village chickens.

The Nottingham–Flybox work suggests a more targeted approach for commercial broiler houses:

• Reserve a small portion of larvae as a daily enrichment ration.
• Scatter them on dry bedding at set times so birds must search and peck.
• Monitor bird behaviour, leg health, and performance over several cycles.

Under NDS1, Zimbabwe has committed to raising livestock productivity while strengthening welfare and sustainability. For integrators and contract growers, a simple management tweak like this could become part of certification schemes or retailer welfare requirements.

Women and youth, who often manage day-to-day flock care, would be central to making such enrichment routines work in practice.

What Comes Next?

The authors are careful to stress that more work is needed, especially on:

• Long-term health outcomes – does increased activity via larvae scattering reduce the actual incidence of leg problems and skin lesions across a full production cycle, and over many flocks?
• Economic modelling – how do the costs of BSFL and labour for scattering compare to potential savings from better welfare and fewer downgrades?
• Farm-scale logistics – how can large houses scatter larvae efficiently and hygienically?

Still, the main message from this study is quietly hopeful: even the heaviest, fastest-growing broilers can be nudged toward more active, more natural lives with a practical, nutritionally integrated tool that doesn’t erode productivity.

For farmers under pressure from buyers and consumers to “do better” on welfare, that matters. It suggests that not every welfare gain requires a new building or a slower breed. Sometimes, it starts with something as small – and as ancient – as a bird scratching in the litter for an insect.

On farms from Nottinghamshire to Norton, if research like this is translated into practice, the sound inside broiler houses may slowly change – a little more rustle of feet on dry shavings, a few more flurries of dustbathing, and the quiet satisfaction of birds allowed, at least in part, to be chickens again.

About The Author

Editor at Large

Farm & Future Africa (FFA) was born from the realization that Zimbabwe’s profound agricultural resilience and innovation needed a clear, authoritative voice to connect with the continent and the world.

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