The Effect of Jungle Light Spectrum on the Fearfulness of Commercial Broiler Chickens

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Master of Science in Animal Welfare and Behavior (MSc AWB)
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animal welfare
animal behavior
animal science
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There is more interest in how food animals are raised. One of the topics of most interest is how commercial broiler houses are lit. There is discussion about high intensity light (50 lux), natural light from windows compared to conventional dim lighting programs (2 – 5 lux) using “white” LED light. Chickens are prey animals that depend on their vision safety. Chickens “see” the word differently than humans and other animals in several significant ways. They have four cones for color vision compared to three for humans. This results in a broader light spectrum range especially in the lower wavelengths. They have very large eyes that when weighted together, weigh more than their brain. They have both binocular and monocular vision and can process two distinct images at the same time. This allows them to see what they are eating and watch for prey at the same time. When designing a lighting program for chickens, these factors must be kept in perspective, so a light environment provides a feeling of safety and provides a spectrum that utilizes their full range. Recreating the lighting that chickens would experience in the wild may provide an environment where they are less fearful. The purpose of this trial was to compare production parameters and determine fearfulness of commercial broilers raised under white LED light of ~3500K and a light spectrum that simulates light in the jungle canopy. Four commercial broiler houses were utilized for the trial each with 19,200 birds. The source flocks were equally distributed within and between the houses. Birds were tested for fearfulness using several behavioral tests at 34 to 36 days of age. Birds were marketed at 54 days of age where performance and Key Welfare Indicators were assessed. Live production parameters nor H:L ratio were influenced by the light spectrum but the results of the inversion test, isolation test and tonic immobility indicated birds raised under a jungle light spectrum were less fearful than birds raised under LED light.

Jennifer Punt, VMD, PhD
Thomas Parsons, VMD, PhD
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