Light spectrum and intensity preferences of broilers

Light is an important management factor in broiler production. Photo: Henk Riswick

Chickens prefer variation in light conditions in their environment to help them with natural behaviours such as foraging and resting.

While scientists know that light is an important management factor in broiler production, there is limited understanding of boiler preferences for different lighting conditions.

Research at Wageningen University and Research in the Netherlands investigated preferences for fast-growing broilers (Ross 308; R) as well as slower-growing broilers (Hubbard JA757; H) for a combination of light spectra of sky blue (S) and green (G) light and intensities (15 lux and 100 lux). They examined 3 study areas:

Where broilers choose to spend most of their time
What behaviours were performed
The feed intake of the birds

A choice test setup was applied where broilers were housed in replicate pens with 4 compartments that they could freely move between, with the 4 light conditions (15S, 15G, 100S and 100G) provided in separate compartments.

The birds’ locations were scored every 5 minutes, 2 days a week, using an automated computer vision approach. Behaviour was observed through instantaneous scan sampling at 5 ages per breed and feed intake was recorded per compartment approximately every week.

Results

The researchers observed that broilers initially spent most of the day in bright green lights (week 1), before a preference for bright sky blue light emerged in weeks 2 and 3 for the fast-growing Ross broilers and week 2 for slower-growing Hubbard broilers.

There was then no clear preference seen for weeks 4-6 for Ross and 3-6 for Hubbard broilers. For Hubbard broilers, a preference for low intensity light was shown in weeks 7 and 8 with no clear preference for green or sly blue light.

Differences were observed in the proportions of behaviours shown in the light treatments, with more inactive behaviour in dimmer, sky blue light conditions and more active behaviours in bright and/or green light conditions.

There was also an initial higher intake in 100G for Ross birds and a higher feed intake in 100S than in 15S late on. For Hubbard birds, there was a higher feed intake at 15 lux than at 100 lux (for both spectra) at the end of the production period.

The outcomes can inform the development of functional lighting programmes for fast and slower-growing broilers and suggest that providing the birds with variation in light conditions in space and time may better suit the birds’ behavioural needs and preferences, potentially improving broiler welfare.

The publication ‘Light spectrum and intensity preferences of fast and slower-growing broilers vary by age, behaviour and time of day’ can be found in the journal Applied Animal Behaviour Science