Why Lighting Programs Matter for Broiler Performance
Lighting is one of the most cost-effective management tools available to broiler growers, yet it is often set once and forgotten. Research shows that well-designed lighting programs can improve FCR by 2–4 points, reduce mortality from metabolic disorders by 20–30%, and improve leg health scores at processing. These improvements come from controlling when birds eat, rest, and are active — all of which affect how efficiently they convert feed into body weight.
The lighting program controls three variables: photoperiod (how many hours of light per day), light intensity (how bright the light is), and the timing and duration of dark periods. Each variable affects bird behavior and physiology differently.
Photoperiod Management
Day-old chicks need near-continuous light (23–24 hours) for the first 3–7 days to help them find feed and water and establish eating behavior. After this adjustment period, a controlled photoperiod should be introduced that includes a defined dark period.
Common photoperiod programs include increasing day length programs, where light duration gradually increases from 18–20 hours at week 2 to 23 hours by week 5 or 6, and constant day length programs, where 18–20 hours of light is maintained from week 2 through processing. Research generally supports increasing day length programs for better overall performance, particularly for FCR and leg health.
The benefits of controlled photoperiods include more synchronized feeding activity, where birds eat more aggressively when lights come on and rest during dark periods, improved feed efficiency because activity during light periods is focused on feeding, reduced metabolic disorders because rest periods allow the cardiovascular system to recover, and better leg health because birds rest more and put less weight-bearing stress on developing legs.
The Dark Period: Essential for Bird Health
A continuous dark period of at least 4–6 hours per day after the first week provides several benefits. It reduces sudden death syndrome and ascites by giving the cardiovascular system a rest period. It improves leg health by reducing the amount of time birds spend standing and walking. It allows birds to rest and reduces overall stress levels. And it can improve FCR by synchronizing feeding behavior and reducing maintenance energy expenditure.
The dark period should be introduced gradually. Abruptly turning lights off on birds that have never experienced darkness can cause panic and piling, leading to mortality. A dimming period of 15–30 minutes before lights-out helps birds settle down. Some controllers support a dusk-to-dawn gradual dimming that mimics natural light transitions.
Light Intensity
Light intensity during the first week should be 20–40 lux to help chicks find feed and water. After day 7, intensity can be reduced to 5–10 lux. Lower light intensity reduces bird activity, which improves FCR by reducing maintenance energy requirements. However, intensity below 5 lux can reduce feed intake and increase the risk of eye abnormalities.
Uniform light distribution across the house is as important as intensity. Dark spots where birds cannot see feeders or drinkers will cause uneven growth. LED lighting provides more consistent light distribution than incandescent or CFL bulbs and uses 70–80% less energy. LED lifespan is typically 50,000+ hours compared to 1,000–2,000 hours for incandescent bulbs.
LED Lighting Considerations
Converting to LED lighting typically pays for itself within 1–2 years through energy savings alone. Additional benefits include reduced maintenance (no bulb changes between flocks), dimmability for gradual light transitions, and the ability to provide specific light spectra. Some research suggests that warm white LEDs (2,700–3,000K) are preferred over cool white, though bird performance differences between spectra in commercial conditions are small.
Not all LED bulbs are suitable for broiler houses. Bulbs must be rated for enclosed, damp, and dusty environments. Dimmable bulbs are needed for gradual on/off transitions. Red or warm-white bulbs are generally preferred over cool-white or blue-toned bulbs.
Tracking Lighting Program Effectiveness
Like all management variables, lighting programs should be documented and reviewed across flocks. Recording the photoperiod schedule, light intensity settings, and dark period duration for each flock, then comparing those records against FCR, mortality, and leg health scores, allows growers to fine-tune their lighting program over time. What works best in one house or climate may not be optimal in another, and the only way to know is to track the data.