Utilizing efficient broiler production with lighting
News - placed on 13/06/2017
Estimated reading time: 6.5 minutes
Editor: HATO Agricultural Lighting
Efficient broiler production requires an optimal environment and therefore an optimal light climate. An ideal broiler environment consists of correct ventilation, the right humidity and temperature in each phase. Lighting, however, is generally underrated in broiler management, even though lighting controls the biological clock. Dawn, dusk, day and night are part of a normal biorhythm, which is a necessity for animal welfare and efficient production.
Stimulating an optimal biorhythm is only possible through a proper lighting management. Due to our 40 years of experience HATO BV is an expert in agricultural lighting. All of our knowledge compiled in our HATO Light Academy enables us to provide lighting solutions for literally everyone. Light is a powerful external stimulus which must be applied efficiently.
Bad lighting can cause various problems in broiler production. Footpad lesions and dermatitis can be indirect results of incorrect lighting. As they are caused by bad litter. Bad distribution of broilers in a production house can cause bad litter, in turn broiler distribution is affected by the light spread resulting in light distribution. A bad light distribution increases the chance of piling and may decrease uniform growth, see figure 1. Bright spots, shadows and resulting in piling of broilers, increase the chance of degradation of the litter.
Light distribution must always be as uniform as possible. Other unwanted (aggressive) behaviour may be caused by a wrong light climate, specifically a wrong light spectrum. An inadequate light program may unintentionally increase mortality rates. Optimizing the light climate is a necessity to prevent an unwanted decrease in broiler production efficiency.
Fig. 1. Ratio between light distribution, piling and uniform growth
To prevent lighting-related issues in broiler production, the provided light climate must meet broiler demands. One of the most important aspects of the broiler’s light climate is the light spectrum. The light spectrum must always correspond to the broiler’s need. Broilers perceive light in different ways than humans and are affected likewise. Due to the difference between our eyes, broilers see the world differently than we humans do. Eyes contain cones and rods, these are photoreceptor cells.
Cones are responsible for sight in photopic, well-lit, conditions. Cones realize colour vision. Poultry have four different kind of cones, whereas humans have three different kind of cones. The human eye is most sensitive to the colour green. Poultry however are sensitive to green, red, blue and (ultra)violet light. The sensitivity peak of both humans and poultry in the green spectrum can be explained by their primary habitat, the forest. The sensitivity peak in the violet spectrum indicates that poultry can even see UV-A.
The difference in spectral sensitivity as shown in figure 2. indicates that light intensity perceived by poultry is higher than light intensity perceived by humans. Almost every part of the spectrum is perceived higher by poultry than by humans. This is why poultry perceive light differently than humans. This means different spectrums lead to a different outcome in intensity perception.
Keeping this in mind, the unit for light intensity – lux – is not suited for measuring light intensity for poultry. Two different spectrums may both lead to measurements of 40 lux, however one can be perceived as 40 lux by poultry and the other can be perceived as 50 lux by poultry. Therefore gallilux is the more appropriate unit for measuring light intensity as poultry perceive it.
Fig. 2. Relative spectral sensitivity of poultry
Broilers receive light through the eyes which affects the photoreceptors in the retina. Light which enters the eyes affects behaviour and internal processes. Light passes through the skull as well where it affects photoreceptors in the hypothalamus, the pineal gland, the pre-optic area and the lateral septal organ. Light that reaches these ‘deep-brain’ photoreceptors affects the biological processes within the broiler. Light regulates the biological clock and the pituitary gland, in turn it affects the regulation of growth hormones and the broiler’s metabolism through the thyroid glands. Lighting affects both behaviour and internal processes and is therefore an extremely important part of the provided environment.
To prevent lighting-related issues the first step is to realize optimal adaptation to the new environment. Lighting is an external stimulus which aids broilers in adapting to their new environment. A well-lit environment helps broilers in finding feed and water during the first 24 or 48 hours. Finding water in particular is really important during the first 24 hours due to a lack of access to water during transport.
A well-lit environment consists, apart from a suitable level of light intensity, of a light spectrum which focusses on the needs of the broiler. A light spectrum close to that of natural daylight would be most optimal when taking broiler vision into account. A light spectrum complying to the needs of broiler vision consists of all – for chicken – visible wavelengths and the right volume of those wavelengths.
When taking into account the deep-brain photoreceptors and the corresponding lighting needs, either a warmwhite light source or a coldwhite light source can be applied.
Broilers do not need a high volume of red wavelengths – warmwhite light source – throughout the entire cycle for optimal production, on the contrary to laying hens which need to get sexually stimulated. It is suggested that broilers desire a proper amount of red wavelengths during the brooding period for early growth. This is generally reached by applying a high light intensity during the first 24 or 48 hours.
A cold white light source, which consists of less red wavelengths may therefore be sufficient as well. However, feedback from practice shows broilers grown to heavy weights – more than 3 kilograms – may in some cases thrive better in warmwhite light sources. A light source capable of fluctuations in colour temperature, much like the sun, would be a very suitable solution to simulate natural daylight.
To acquire optimal adaptation and optimal production, more is needed than the right light source and a good light spectrum. A good lighting system must be accompanied by good light management. Good light management consists of the right photoperiod and light intensity during the production cycle.
Research (2012, Schwaen-Lardner, K.) showed that the highest growth rate at different ages was reached at 20 hours of light. Both short daylengths (14L) and longer daylengths (23L) had a negative impact on growth rate (table 1).
Table 1. Impact of daylength on bodyweight
The same research showed that looking at the welfare aspect of the broiler, long daylengths are unacceptable. The best welfare is seen at 17 hours of light (table 2).
|14 hours of light||17 hours of light||20 hours of light||23 hours of light|
|Inactive resting||+||++||-||- -|
|Feeding||++||++||- -||- -|
|Dustbathing||++||++||- -||- -|
Table 2. The effects of day length on broiler welfare
When taken the information on welfare and production results into account, the optimal day length for broilers appears to be between 17-20 hours of light. Recommended is 17-18 hours of light during the grow- out period. A longer photoperiod will increase mortality, animal welfare and the electricity bill. A shorter photoperiod will decrease growth.
During the brooding period a light intensity of at least 40 lux should be applied to accompany the long photoperiod in aiding the chicks with finding water and feed. After the brooding period the light intensity can be decreased to a light intensity of 5 to 10 lux which is sufficient for optimal growth. There are however other light programs which may be effective as well. Lighting management is always subject to local legislation.
Since light is an extremely powerful external stimulus, providing an optimal light climate to broilers is a necessity. Simulating natural daylight will realize good vision and will foresee in the needed wavelengths for biological processes. Providing an uniform light distribution helps in preventing bad litter and consequently health problems. Applying the right light management is important. The right light program, including the right light intensity and photoperiod at the right time is needed to optimize overall production and to secure animal welfare.
Remember: Light proves to be a valuable asset of your climate management.
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