1. Introduction
Lighting management is a critical yet often underestimated factor in modern poultry production. As global demand for poultry meat continues to rise, optimizing lighting conditions has emerged as a cost-effective tool to enhance broiler welfare, mitigate environmental stressors, and improve productivity. This article synthesizes recent research on lighting programmes, intensity preferences, and circadian rhythm entrainment in broilers, offering actionable insights for producers and researchers alike.
2. The Role of Lighting Programmes in Broiler Management
Lighting programmes manipulate photoperiods (light-dark cycles) to regulate broiler behavior and physiology. Studies demonstrate that tailored photoperiods can reduce heat stress impacts, particularly in hot climates. For instance, intermittent lighting schedules allow broilers to feed during cooler hours, minimizing heat-induced feed intake suppression and improving growth rates. A 2016 review highlighted that adaptive photoperiods enhance immune responses and overall welfare by aligning feeding activity with thermoregulatory needs.
Notably, while lighting programmes influence feed intake and stress resilience, they may not affect all health metrics. A 2017 study found no significant correlation between lighting periods (constant, declining, or growing light) and footpad lesions, suggesting that other factors, such as litter quality, play a more direct role in dermatological health.
3. Light Intensity Preferences and Welfare Implications
Broilers exhibit distinct preferences for light intensity, which directly impacts their behavior and welfare. A 2019 study developed a choice system to evaluate preferences, revealing that 20 lux (compared to 5 lux) attracted more birds to feeding areas and increased feed consumption. This aligns with observations that higher light intensities stimulate foraging and feeding activities, whereas dimmer environments (1–2 lux) are preferred for resting.
These findings challenge traditional industry practices that use uniformly low light intensities to reduce aggression. Instead, a compartmentalized approach—20 lux near feeders and waterers, with reduced intensity elsewhere—balances productivity and welfare. Such strategies comply with evolving regulations advocating for species-specific lighting standards.
4. Circadian Rhythms and Extraretinal Photoreception
Broilers, like many birds, possess extraretinal photoreceptors that entrain circadian rhythms independently of vision. A seminal 1977 study showed that blinded chickens synchronized their locomotor activity to light-dark cycles, underscoring the role of non-visual photoreceptors in regulating biological rhythms. This mechanism explains why even subtle lighting changes can influence broiler behavior, such as sleep-wake cycles and metabolic processes.
Modern applications of this knowledge include dynamic lighting systems that mimic natural dawn-dusk transitions, reducing stress and promoting natural behaviors. For example, gradual dimming at night may prevent abrupt changes that disrupt rest, thereby improving weight gain and feed efficiency.
5. Mitigating Heat Stress Through Lighting Interventions
Heat stress remains a major challenge in poultry farming, particularly in tropical regions. Lighting programmes that restrict feeding to cooler periods (e.g., early morning or late evening) help broilers maintain feed intake and growth under thermal stress. Additionally, night light regimens have been explored for their antioxidant benefits. A 2019 trial on Lingnan Yellow broilers found that controlled night lighting improved antioxidant enzyme activity, potentially reducing oxidative damage during rapid growth phases.
6. Welfare-Driven Innovations in Lighting Design
The push for ethical poultry production has spurred innovations in lighting design. For instance:
Spectral Modulation: Blue and green wavelengths are being tested for their calming effects, while red light may enhance growth rates.
Dynamic Intensity Systems: Automated systems adjust light intensity based on bird age and behavior, reducing energy use while meeting welfare needs.
Dark Periods: Incorporating uninterrupted darkness (4–6 hours daily) supports rest and skeletal development, addressing leg health issues prevalent in fast-growing strains.
7. Economic and Environmental Synergies
Optimized lighting strategies yield economic benefits by lowering mortality rates and improving feed conversion ratios. For example, a 2025 techno-economic analysis of Thai broiler farms highlighted that integrating energy-efficient LED systems with renewable energy (e.g., biogas from poultry waste) could reduce operational costs by 15–20%. Furthermore, reduced light intensity in non-feeding areas decreases electricity consumption, aligning with sustainability goals.
Lighting is not merely a tool for visibility but a multifaceted lever to enhance broiler welfare, productivity, and sustainability. By adopting evidence-based lighting programmes—such as compartmentalized intensities, circadian-aligned photoperiods, and heat stress-mitigating schedules—producers can meet ethical and economic demands in a rapidly evolving industry. As research continues to unravel the complexities of avian photoreception and behavior, the future of poultry farming lies in harmonizing technology with biological insights.