Importance of Dynamic lighting programs to optimize broiler health and welfare
Broiler chickens rapidly progress through different life stages, each requiring specific inputs depending on their developmental stage. For example, broilers’ feed composition and housing temperature are specified based on their age. Although lighting is recognized as an important environmental input for broilers, the optimal lighting conditions for broilers at each life stage are not well-defined.
In nature, lighting intensity, spectrum, and distribution are highly dynamic (changing over time). This dynamic nature is due to differences in sun angles by the time of day, year, or latitude, by weather patterns affecting clouds or particulate matter in the atmosphere, and by the influence of vegetation on filtering and reflecting sunlight that reaches the ground. Poultry have been selected to anticipate a dynamic lighting environment, which serves as adding complexity and serving as an environmental enrichment.
Typical broiler lighting programs utilize a relatively static lighting schedule. Broiler chicks are typically reared under a 23 or 24-hour photoperiod (light-on) schedule for the first week of brooding, after which they are moved to a 16-18-hour photoperiod. Lighting is typically brighter (30-50 lux) for brooding, and then lights are dimmed after (20 lux mandated for E.U., often as low as two lux for other geographies). Often, only one spectrum of “white” lighting is used, often “cool” white light coming from >4000 K LEDs or compact fluorescent lighting.
This relatively static lighting schedule has been born out of technological limitation rather than representing the optimal lighting schedule for broilers. Historically, lighting systems have been controlled by a single central controller, lights typically have limited dimmability and no spectral flexibility. This limitation of the lighting infrastructure has also limited research into broiler lighting programs, where only a single lighting factor (intensity, spectrum, or schedule) has been typically evaluated at a time.
NatureDynamics System 
To enable a fully dynamic lighting program for poultry, Once by Signify developed a revolutionary lighting system, called NatureDynamics®. This spectrally tunable lighting system is capable of dialing in and mixing precise red, green, and blue lighting spectra. The system is controlled by a wireless mesh network, called Zigbee, with a similar architecture as Philips Hue® lighting system. Lights are commissioned onto a gateway controller and can be assigned to one of up to 16 zones. Each zone can run a lighting “recipe.” Lighting recipes specify the RGB setpoints according to time of day and day of production. Administration of the system is completed using Signify’s Interact Agriculture® Mobile App, available through the Apple’s App Store for iOS mobile devices or through Google Play for Android mobile devices. Lighting recipes are loaded onto the gateway via the Interact Agriculture app.
In addition to loading and changing recipes, the Interact Agriculture app enables the use of lighting Overrides. These overrides are user defined RGB setpoint that can be initiated for a set period of time, usually on the scale of 30 minutes to a few hours. These overrides can be used to enable bird health checks, depopulation of the barn during catch, application of vaccines, and cleanout between flocks.
Junglite Recipe
With the added dynamic functionality of the NatureDynamics lighting system over traditional broiler lighting systems, ONCE researchers set out to understand how more precise control of intensity, spectrum and schedule could positively impact broiler health and welfare. Through a series of preference trials and pen research trials, along with existing published research, eight common themes emerged:
- Full-spectrum lighting (mixed red, green, and blue) is preferred by broilers compared to monochromatic colors.
- Younger broilers prefer brighter light than do older broilers.
- Younger broilers prefer lighting with a higher proportion of red spectral contributions, and older broilers prefer lighting with a higher proportion of blue spectral contributions.
- Red spectra promote activity and aggression, which translates to better starting for brood. 5) Blue spectra have a calming effect, resulting in better feed conversion and growth rates for older broilers.
- As birds grow older, they can withstand longer dark periods (scotophase) without detriment to performance, and to the benefit of welfare.
- Abrupt changes in intensity or photoperiod from one production day to the next negatively impacts bird performance.
- Simulated sunrise and sunset via 30-minute intensity ramping results in lower stress to the animals.
Integrating these findings into a single lighting recipe, ONCE developed the Junglite® recipe. The patented Junglite recipe consists of two lighting setpoints: “Jungle Green,” used for brood, and “Jungle Sky,” used for grow-out. Jungle green is a mixture of red, green, and blue with a higher proportion of red and green spectra and appears greenish white to the human eye. This spectrum results in active chicks that can find food and water under a high color-rendering index spectrum. Jungle Sky is a mixture of green and blue lighting with a higher proportion of blue spectra and appears bluish white to the human eye. This spectrum results in calmer birds during the grow-out phase, which reduces stress and promotes efficient growth.
The Junglite recipe employs long photoperiod (23 hrs.) for brooding, shorter photoperiod (16-18 hrs.) for grow-out, and gradual day-by-day transitions in photoperiod between phases. Likewise, the transition from Jungle Green spectrum during the first 14 days of brood to Jungle Sky spectrum from 20 days post hatch is also changed gradually day-by-day as to not impose any additional stress on the birds. Finally, light intensity is initially 50-75 lux during brood and 10-15 lux during grow-out and is changed gradually day-by-day from days 14-20. Each morning, a gradual introduction of sunlight is introduced via a simulated sunrise over a period of 30 minutes, and each evening, a gradual removal of light is given via a
simulated sunset over a period of 30 minutes. Thus, gradual changes of lighting conditions within a day or between days reduces stress.
Welfare Benefits and Production Benefits
The Junglite recipe was first developed and assessed in a small research setting. Once it was refined, it was brought into commercial broiler houses for thorough testing. In the 43 commercial trials tested worldwide to date, it was found that the dynamic Junglite recipe resulted in a 2.2 Feed Conversion Ratio (FCR) point improvement compared to lighting programs utilizing white LEDs. There were no significant differences seen in growth rate or livability. The European Broiler Index was improved by 9.81 points under Junglite. These performance improvements are thought to be the result of lower stress and improved welfare. In fact, broilers grown under the Junglite recipe had significantly lower physiological indicators of stress including lower Heterophyl:Lymphocyte ratios and lactate levels. Broilers also showed significantly lower indicators of fear under the Junglite recipe, including tests for tonic immobility, inversion wing flapping, isolation vocalizations, time to emergence, and avoidance distance tests. Altogether, the Junglite recipe has been found to improve production and welfare, representing a clear win/win for the producer and the bird.
Conclusion
Natural lighting tends to be dynamic in nature. The ONCE NatureDynamics for broilers enables optimization of spectrum and intensity over a defined schedule. The Junglite recipe defines the optimized lighting conditions that borrow from nature and result in scientifically proven improvements in production and welfare for broilers.
