Broiler Lighting Systems: Optimizing Growth, Welfare, and Production Efficiency
Lighting regimens are critical determinants of broiler performance, health, and welfare. This review synthesizes current research on photoperiods, light intensity, spectra, and modern LED technologies, highlighting their impacts on growth metrics, physiological stress, and economic outcomes. Evidence-based recommendations are provided for optimizing lighting systems in commercial broiler production.
1. Introduction
Broiler chickens (Gallus gallus domesticus) are highly sensitive to light conditions due to their evolutionary adaptation to diurnal rhythms. Modern poultry production relies on tailored lighting systems to maximize growth rates, feed efficiency, and animal welfare while minimizing energy costs. This article evaluates key lighting parameters—photoperiod, intensity, spectrum, and light source—drawing on empirical studies from the past decade.
2. Photoperiod: Balancing Growth and Welfare
2.1 Intermittent Lighting vs. Continuous Lighting
Intermittent lighting (e.g., 16L:8D cycles) reduces metabolic stress and improves leg health compared to continuous lighting (24L:0D) (Mendes et al., 2020, Poultry Science).
Economic benefit: Intermittent programs lower energy use by 18–22% without compromising body weight gain (Oliveira et al., 2019).
2.2 Dark Periods and Skeletal Health
Minimum 4 hours of darkness daily is essential to mitigate tibial dyschondroplasia and sudden death syndrome (Blatchford et al., 2012, British Poultry Science).
Prolonged darkness (>6 hours) enhances melatonin secretion, improving immune function (Xie et al., 2021).
3. Light Intensity: From Hatch to Harvest
3.1 Early Rearing Phase (0–7 Days)
High intensity (≥20 lux) stimulates feeding behavior and early growth (Deep et al., 2013).
Caution: Excess light (>50 lux) may increase aggression and mortality (Kristensen et al., 2006).
3.2 Grow-Out Phase
Reduced intensity (5–10 lux) lowers activity levels, directing energy toward muscle deposition (Hassan et al., 2021, Journal of Applied Poultry Research).
Dim-to-dark transitions prevent retinal damage and stress during handling (Prescott & Wathes, 2002).
4. Spectral Sensitivity: The Role of Wavelength
4.1 Blue Light (450–495 nm)
Enhances feed intake and weight gain by stimulating hypothalamic appetite pathways (Riber, 2015).
Overexposure disrupts circadian rhythms, increasing plasma corticosterone (Jiang et al., 2020).
4.2 Red Light (620–750 nm)
Promotes calm behavior and reduces feather pecking (Li et al., 2022).
Limitation: Poorer feed conversion ratios compared to blue light (Pan et al., 2021).
4.3 Broad-Spectrum White LED
Mimics natural daylight, balancing growth and welfare metrics (Yang et al., 2018).
Energy efficiency: 40% lower power consumption vs. incandescent bulbs (Leeson & Walsh, 2020).
5. Advanced Lighting Technologies
5.1 Tunable LED Systems
Programmable spectra and intensities allow phase-specific optimization (e.g., blue light for early growth, red light for finishing) (Xiong et al., 2023).
Cost barrier: High initial investment limits adoption in small-scale farms (Liu et al., 2022).
5.2 Smart Lighting Controls
IoT-enabled systems adjust lighting in real time based on bird activity and environmental sensors (Wang et al., 2021).
Case study: A Thai commercial farm reported a 7% reduction in FCR (feed conversion ratio) after implementing adaptive lighting (Charoensook et al., 2023).
6. Welfare and Ethical Considerations
Flicker-free lighting: High-frequency LEDs (>1,000 Hz) prevent retinal stress and aversion behaviors (Nääs et al., 2020).
EU Directive 2007/43/EC: Mandates minimum light intensity (≥5 lux) and 6 hours of darkness for broilers.
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