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.

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