Date of Graduation

5-2026

Document Type

Thesis

Degree Name

Bachelor of Science in Agricultural, Food and Life Sciences

Degree Level

Undergraduate

Department

Animal Science

Advisor/Mentor

Dr. Shawna Weimer

Committee Member

Dr. Danielle Graham

Second Committee Member

Dr. Sara Orlowski-Workman

Abstract

The broiler chicken industry has increased the number of birds produced each year,

making the mitigation of stressors that affect broiler health and meat quality increasingly

important. New management strategies, like lighting protocols, could help combat stressors and

promote behavioral indicators of positive welfare. This study compared the effects of blue-green

and white light on broiler fear response using a tonic immobility test and behavioral repertoire in

the home pen using continuous focal sampling. Day-of-hatch male broiler chicks (N=600) were

randomly divided into 12 pens (n=50 chicks/pen). The pens had either a white LED light

(control, n=6) or a blue-green spectrum LED light (treatment, n=6). After 12 days, 3 birds per

chamber were tested for tonic immobility (TI), which involved placing the birds backwards on a

V-shaped cradle for a maximum of 300 seconds, and the latency for the bird to right itself

(seconds) was recorded. On day 13, the behavior of one chick per room (n=12) was observed for

9 behaviors (walk, stand, run, peck, preen, stretch, sit, drink, and eat) for 30 minutes in the

morning (0930) and in the afternoon (1400). Behavior was observed using continuous focal

sampling, and the duration of each behavior bout was recorded manually and using Noldus

Observer XT 14 software. The results for TI revealed that there was no significant light effect on

chicken latency to the right, but there was a numerical one, with birds from the control taking

137 seconds to the right compared to 115 seconds for the treatment. Lighting treatment had few

significant effects on the percentage a bird spent in each behavior. Time of day had a greater

influence on behavior, with birds spending a greater percentage of time drinking in the morning

(p=0.02) and pecking in the afternoon (p< 0.0001). The interaction between light and time of day

was significant for pecking behavior, with control birds pecking the lowest percentage of time in

the morning (p=0.02) compared to both treatments in the afternoon. There were no significant

2differences observed for all other behaviors for time of day, lighting treatment, or the interaction

between the two. Overall, lighting treatment had minimal impact on broiler behavior and fear,

but this could largely be due to the small sample size used in the study. Future research should be

done using a larger sample size to get more comprehensive results.

Keywords

Broilers, Spectrum Lighting, Tonic Immobility, Broiler Behavior

Download

Share

COinS