Discover how strategic light-dark cycles are improving broiler health, welfare, and production efficiency
Walk into any modern broiler chicken house, and you'll notice something surprising – the lights flicker on and off throughout the day in a carefully choreographed pattern. This isn't an electrical problem; it's a sophisticated management strategy that's revolutionizing poultry production worldwide.
As the global demand for animal protein continues to grow, producers are turning to innovative techniques that promote both animal welfare and production efficiency. Among these, intermittent lighting has emerged as a powerful, non-invasive approach that delivers remarkable benefits across the board – from stronger legs and healthier immune systems to improved survival rates and better feed conversion.
Lighting represents far more than just illumination in the world of poultry science. For broiler chickens, light intimately influences their circadian rhythms, physiological functions, and even hormonal secretions 2 .
While continuous lighting was once standard practice in many poultry operations, research now demonstrates that strategic alternation of light and dark periods – known as intermittent lighting – can stimulate natural behaviors, reduce stress, and ultimately produce healthier, more robust birds 7 . The implications extend beyond the farm gates, potentially influencing everything from meat quality to the environmental footprint of poultry production.
To understand why intermittent lighting proves so effective, we must first appreciate how chickens perceive and respond to light. Broilers experience light differently than humans – their visual system is more complex and sensitive. With a wider color spectrum, broader visual field, and higher sensitivity to flickering, chickens detect nuances in lighting that we cannot 2 .
Light penetrates chickens through their eyes and directly through their skull to photosensitive brain regions 2 .
Light signals trigger hormone production in the pineal gland and hypothalamus, regulating growth and development 2 .
When light signals reach these brain regions, they trigger a cascade of neuroendocrine responses that affect everything from feeding behavior to immune function. This explains why lighting regimens can have such profound effects on poultry – they're not just influencing what chickens see, but directly modulating their biology at a fundamental level.
Scientific investigations into intermittent lighting have consistently demonstrated significant advantages over traditional continuous lighting programs. These benefits span multiple aspects of broiler production, creating a compelling case for adopting this approach.
Intermittent lighting groups showed significantly fewer and less severe leg abnormalities due to increased activity and movement 1 .
Birds under intermittent lighting coped significantly better with necrotic enteritis challenges, showing less impact on feed efficiency 4 .
A comprehensive 2020 investigation directly compared continuous and intermittent lighting programs with 600 Cobb-500 broiler chicks divided into six groups with different lighting schedules 5 .
600 one-day-old chicks divided into 6 groups with 5 replicates each
Included continuous light (22L, 20L, 18L) and intermittent schedules (1L:3D, 5L:1D, 3L:1D)
42-day experimental period tracking performance and health metrics
The 3L:1D intermittent schedule yielded the best feed conversion ratio (1.62) and lowest mortality (3.2%), along with enhanced innate immunity and oxidative status 5 .
| Lighting Program | Final Body Weight (g) | Feed Conversion Ratio | Mortality (%) |
|---|---|---|---|
| CL22 (Continuous) | 2,670 | 1.72 | 4.2 |
| IL22 (11L:1D) | 2,580 | 1.68 | 3.8 |
| CL20 (Continuous) | 2,610 | 1.70 | 4.0 |
| IL20 (5L:1D) | 2,560 | 1.66 | 3.5 |
| CL18 (Continuous) | 2,540 | 1.69 | 3.9 |
| IL18 (3L:1D) | 2,520 | 1.62 | 3.2 |
Data source: 5
Implementing and studying intermittent lighting programs requires specific tools and equipment. Here are some of the key components researchers use in this field:
Provide precise, energy-efficient light with specific wavelengths for studying light color and intensity effects 2 .
Automate complex intermittent schedules with precise timing across experimental groups 5 .
Measure light intensity at bird level to maintain consistent conditions and welfare standards 2 .
Measure gas exchange and heat production to quantify energy expenditure under different regimens 3 .
The evidence supporting intermittent lighting continues to grow, painting a compelling picture of an approach that benefits birds, producers, and consumers alike. By aligning more closely with natural biological rhythms, intermittent lighting creates a less stressful environment that allows broilers to express more natural behaviors while maintaining strong production metrics.
As consumer interest in animal welfare grows and regulations increasingly phase out antibiotic use in animal agriculture 4 , intermittent lighting offers a viable, non-medicated strategy to enhance poultry health and resilience.
Looking ahead, research continues to refine our understanding of optimal lighting regimens. Scientists are exploring how to tailor programs for different breeds, climates, and production goals. Some researchers are investigating "variable light intensity" programs that allow birds to self-select their preferred light environments for different activities 8 , potentially offering even more nuanced approaches to poultry welfare.
What began as simple observations of chicken behavior under different light conditions has evolved into a sophisticated science that demonstrates how small changes in management practices can yield substantial benefits. Intermittent lighting represents a powerful example of how working with, rather than against, natural biology can create more sustainable, ethical, and efficient food production systems.