Effect of Light On Egg Production | Poultry Lighting for Egg Production
Directory:
1. Effect of LED Light Color on Laying Hens
2. Effect of LED Light Intensity on Laying Hens
3. Effect of LED photoperiod on laying hens
Poultry possess a highly sensitive visual response system that can adapt to varying lighting conditions through the retina and sensory nerves located beneath the skull. This system influences body development and behavior by regulating metabolism and hormonal changes. In humans, the retina contains three types of cones: L, M, and S, which have peak spectral sensitivities at 650 nm, 535 nm, and 440 nm, respectively. In contrast, poultry have a fourth type of cone with a peak sensitivity at 415 nm, enhancing their light sensitivity. This unique physiological structure highlights the significance of the light environment in the production of laying hens, as it directly or indirectly impacts their growth, development, production performance, and behavior through various mechanisms. In modern laying hen production, closed chicken houses rely on artificial lighting as the sole controllable light factor. Implementing scientific and appropriate lighting can optimize laying hens' production performance while ensuring their welfare.
1. Effect of LED Light Color on Laying Hens
The primary distinction between LED lights and traditional light sources is their strong monochromatic nature. When combined with intelligent control systems, LEDs can offer "one light with multiple colors, arbitrary conversion." These features lead research on LED lighting to focus on light color, examining how monochromatic light affects the growth, development, and production performance of laying hens. Poultry have a broader visible spectrum than humans and can differentiate between various colors. Exposure to different light colors can alter their biological rhythms and production performance. Additionally, laying hens have varying light requirements at different growth stages. Therefore, understanding the effects of light color on laying hens throughout their growth phases is crucial for the effective use of monochromatic LEDs and for guiding production practices appropriately.
1.1 Effect of LED Light Color on Laying Hens' Behavior
Different light colors create distinct effects that can influence laying hens' behavior in varying degrees. Hubereiche et al. observed the behavioral patterns of laying hens under red, white, and green light, finding that hens exhibited more exploratory behaviors (such as foraging and pecking) under green light, while their aggressiveness was lower under red light compared to white light. Conversely, research by Sultana et al. indicated that laying hens became more aggressive under red light, while blue light exposure led to reduced activity levels, resulting in quieter chickens.
1.2 Effect of LED Light Color on the Physiology and Production Performance of Growing Chickens
The use of monochromatic light during the growth phase significantly influences the sexual maturity of laying hens, subsequently affecting their production performance later on. Research indicates that 14-week-old laying hens exposed to blue light experienced a notable delay in laying time compared to those under red and white light. In a study by Hassan et al., various monochromatic LED lights and their combinations were applied to 12-week-old laying hens. The findings revealed that hens treated with blue light (63.63 g) and green light (63.06 g) produced eggs with significantly greater weight than those under red light (61.76 g) and other light combinations, with the green light group also showing a marked increase in eggshell strength (P<0.05). Additionally, hens under red light exhibited a higher feed conversion rate and more pronounced eggshell coloring. Furthermore, a combination of red and green light (14 hours of red light plus 2 hours of green light) enhanced the secretion levels of FSH and E2 in laying hens, promoting ovarian development and increasing egg production.
1.3 Effect of LED Light Color on the Physiology and Production Performance of Laying Hens
Applying blue light during the laying phase (at 19 weeks of age) can enhance egg production and feed conversion rates in laying hens. However, the growth trend of egg weight under blue and red light is slower compared to that under white and green light. Moreover, hens exposed to red light had higher fertilization and hatching rates than those under blue and green light, with significantly elevated levels of FSH and LH in the red light group compared to the green light group. The type of light provided during peak egg-laying periods greatly influences egg production levels. Blue light treatment promotes the secretion of LH and FSH, leading to increased egg production and a reduced feed-to-egg ratio.
The influence of light color on laying hens primarily pertains to sexual maturity and production performance. Different light color treatments should be implemented for laying hens at various growth stages to achieve specific objectives. However, the research on the effects of light color on the behavior of laying hens is still limited and contentious, warranting further investigation and analysis.
2. Effect of LED Light Intensity on Laying Hens
2.1 Effect of LED Light Intensity on Laying Hen Behavior
It is widely accepted that chickens exhibit minimal activity in dark conditions, with a significant increase in activity occurring at the start of the light cycle. This indicates a strong correlation between light intensity and the behavioral patterns of laying hens. Wang et al. studied feather pecking behavior in chicks at four different light levels: 5. 10. 15. and 20 lx, and assessed skin damage. The areas affected on laying hens included the tail (44.02%), back (20.8%), and head (15.73%), with damage severity rising alongside light intensity. The influence of various LED light intensities on laying hens mirrors that of conventional light sources, as both feather pecking and anal pecking behaviors increase with higher light intensity, leading to greater activity levels and increased energy expenditure.
2.2 Effect of LED Light Color and Intensity on Laying Hens
Poultry possess a unique visual system that makes them more sensitive to light within the 400-480 nm and 580-700 nm ranges compared to humans. Consequently, under specific light colors, poultry perceive illumination differently than humans do. In practical settings, light source illumination is typically based on human eye standards, often using white light standards even in monochromatic lighting, which lacks a scientific basis. Therefore, a thorough investigation into the interaction between light color and intensity is crucial for optimizing the use of LED lights in laying hen production. Currently, researchers have conducted extensive studies on the effects of light color due to the superior monochromaticity of LED lights, but there is limited research on the interaction between monochromatic light and intensity. Qi Xianli et al. examined 3.600 commercial laying hens under four light colors (red, green, blue, and white) at nine different illumination levels (0.1. 0.5. 1. 2.5. 5. 10. 15. 20. 25. and 30 lx). They evaluated various indicators such as mortality rate, feed consumption, egg production, and pecking habits to summarize the effects of light color and intensity on laying hens. The findings indicated that as illumination levels increased, the age of sexual maturity in laying hens was advanced under different light colors.
The use of monochromatic light in production practices is already widespread, but there is still a need for more precise methods of selecting monochromatic light and other related lighting parameters. To address this issue, the Key Laboratory of Facility Agriculture Engineering at China Agricultural University has developed an autonomous preference selection system to study how light color affects laying hens. The author has also been investigating the effects of combining blue LED lights with light intensity on growing chickens. Initial findings indicate that exposure to blue light may delay the sexual maturity of laying hens, while using a higher illumination level than white light can promote better growth and development in these birds.
3. Effect of LED photoperiod on laying hens
Regarding the influence of LED photoperiods on laying hens, it is important to note that natural lighting varies with the seasons, and this seasonal change is essential for hens to optimize their egg-laying capabilities. In a controlled chicken house, aligning the artificial light source's operating hours with the hens' biological rhythms is crucial for their production performance.
The impact of photoperiod on laying hen productivity primarily stems from variations in lighting duration, with the type of light source having little effect. Kamanli et al. conducted a study comparing the effects of three different light sources—yellow incandescent bulbs, white mini fluorescent lamps, and white LED lamps—on laying hen performance and egg quality under identical photoperiods. Their findings revealed that the type of light source did not significantly influence the final weight, feed intake, egg production, egg protein index, or morphological characteristics of the hens. Thus, the effects of LED light cycles on laying hens are comparable to those of traditional lighting sources.
3.1 Effect of LED Light Cycles on the Production Performance of Laying Hens
The typical light cycle implemented in production is 16 hours of light and 8 hours of darkness (16L:8D). Numerous studies indicate that intermittent lighting can reduce the duration of light exposure and lower costs while maintaining or even enhancing the egg-laying performance of hens. Ma et al. examined the egg production and energy efficiency of hens under two lighting schedules: 13L:5D:1L:5D and 16L:8D. Their findings revealed that the average daily egg production for hens aged 18 to 58 weeks was (60.8±19.2)% in the intermittent lighting group and (59.7±19.3)% in the continuous lighting group. By 58 weeks, hens in the intermittent lighting group produced 7 more eggs than those in the continuous lighting group, with no significant difference in feed intake, suggesting that intermittent lighting enhances feed conversion efficiency. Shen's research compared the effects of two intermittent lighting schedules with continuous lighting and found that while egg quality was not significantly affected by different light cycles, egg production in the intermittent lighting group increased notably. Additionally, compared to continuous short-term lighting, a gradually decreasing lighting schedule (from 23 to 8 hours) during the rearing phase delayed the onset of laying. In continuous lighting, hens exposed to 8 hours of light experienced a delay in sexual maturity of 18.3 days compared to those in a 10-hour light environment, indicating that longer lighting periods during rearing can promote sexual maturity in hens.
3.2 Effect of LED Photoperiod on Laying Hen Mortality Rates
Lewis et al. studied the mortality rates of laying hens under various intermittent lighting conditions and found that shorter daytime lighting effectively reduces mortality rates, with a 0.8% increase in mortality for every additional hour of light exposure. The superior monochromaticity of LED light sources has led to the growing use of monochromatic lighting in production. However, the combined effects of monochromatic light, illuminance, and lighting systems remain unclear and require further investigation. Additionally, as laying hen farming practices evolve, lighting arrangements in housing should adapt to spatial changes. The benefits of LED lamps, such as their compact size, versatile installation options, and adjustable light parameters, can be leveraged to develop lighting solutions tailored to different breeding methods. Furthermore, aligning the lighting system with the varying light environment needs of hens at different life stages through the effective integration of intelligent environmental control systems and LED lamps is crucial for the scientific and efficient management of laying hen production.