Research note: assessing disturbance and its impact on behavior in the early-life of broiler chicks

Authors: JACKSON, A - Auburn University; LANDERS, D - Auburn University; Purswell, Joseph; BAKER-COOK, B - Auburn University

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/27/2025
Publication Date: 5/28/2025
Citation: Jackson, A., Landers, D., Purswell, J.L., Baker-Cook, B. 2025. Research note: assessing disturbance and its impact on behavior in the early-life of broiler chicks. Poultry Science. 104(2025)105355. https://doi.org/10.1016/j.psj.2025.105355.
DOI: https://doi.org/10.1016/j.psj.2025.105355

Interpretive Summary: Behavioral disruption, when a behaviour an animal is performing gets disrupted by another animal, causes stress and frustration as the need to perform the behaviour is interrupted or not met. The stress from repeated behavioral disruptions can reduce bird health, disease resilience, growth and productivity. We carried out a study looking at behavior disruption in the first week of life in broiler chickens. Behavioural analysis was used to determine which time of day behavioural disruption is most likely to occur, how age impacts behavioural disruption, and whether birds are likely to return to a behaviour that has been disrupted. It was found that the occurrence of disruptions decreased over the seven days, and that disruptions are most likely to occur around mid-day, afternoon and evening. Birds were most likely to return to locomotive, sitting, sleeping, drinking, eating, and preening, then allopreening, explorative, play or comfort. This information will provide scientists with a better understanding of when behavior disruption occurs during early life and which behaviors chicks prioritize the performance.

Technical Abstract: Behavioral disturbance in poultry is relatively understudied; however, it plays an important role in influencing bird well-being. While disturbance to rest has been well-examined, all behaviors are susceptible to disturbance and merit evaluation. This study assessed behavioral disturbances in broiler chicks during the first week of life, focusing on variations in age, time of day, and the impact of disturbance on behavior performance. Seventy-five mixed-sex chicks were randomly placed into three pens (25 birds/pen), with three focal subjects per pen (n=9). Behavior was continuously recorded from days 1 to 7 of age. Chick behaviors assessed include locomotive, sleeping, sitting, eating, drinking, preening, allopreening, comfort, exploratory, and play. Disturbances were recorded and analyzed for frequency by age and time of day. The likelihood of chicks resuming a behavior post-disturbance was calculated. One-way ANOVAs were conducted to assess the impact of age and time of day on disturbance frequency and behavior type on the return to behavior. The frequency of disturbances was highest on day 1 of age, with exception of day 2. Disturbances decreased on day 3 of age and then declined further on Day 6 (P<0.01). Furthermore, disturbance to behavior occurred more during the mid-day period, afternoon, evening than the pre-dark period and morning period (P<0.01). The type of behavior (P < 0.01) disturbed also affected the likelihood of return, with chicks more likely to resume locomotive, sitting, sleeping, drinking, eating, and preening behaviors than allopreening, exploratory, play, or comfort behaviors. Overall, chick age and time of day influenced the frequency of behavioral disturbances during the first week of life. Additionally, the type of behavior performed pre-disturbance did affect the likelihood of returning to that behavior. These findings highlight the potential impact of environmental novelty post-placement and chick diurnal activity during early-life have on disturbance frequency, and how the function of behaviors influence their return post-disturbance. Further research is needed to assess the long-term impact of disturbance on the behavior and well-being of birds.