The Sequential Behavior Pattern Analysis of Broiler Chickens Exposed to Heat Stress

Abstract

Broiler productivity is dependent on a range of variables; among them, the rearing environment is a significant factor for proper well-being and productivity. Behavior indicates the bird’s initial response to an adverse environment and is capable of providing an indicator of well-being in real-time. The present study aims to identify and characterize the sequential pattern of broilers’ behavior when exposed to thermoneutral conditions (TNZ) and thermal stress (HS) by constant heat. The research was carried out in a climatic chamber with 18 broilers under thermoneutral conditions and heat stress for three consecutive days (at three different ages). The behavior database was first analyzed using one-way ANOVA, Tukey test by age, and Boxplot graphs, and then the sequence of the behaviors was evaluated using the generalized sequential pattern (GSP) algorithm. We were able to predict behavioral patterns at the different temperatures assessed from the behavioral sequences. Birds in HS were prostrate, identified by the shorter behavioral sequence, such as the {Lying down, Eating} pattern, unlike TNZ ({Lying down, Walking, Drinking, Walking, Lying down}), which indicates a tendency to increase behaviors (feeding and locomotor activities) that guarantee the better welfare of the birds. The sequence of behaviors ‘Lying down’ followed by ‘Lying laterally’ occurred only in HS, which represents a stressful thermal environment for the bird. Using the pattern mining sequences approach, we were able to identify temporal relationships between thermal stress and broiler behavior, confirming the need for further studies on the use of temporal behavior sequences in environmental controllers.

Welfare of broilers on farm

“…When the temperature increases, broilers will change their behaviour to try to cope with the heat stress. They will reduce eating and increase drinking behaviour (Chowdhury et al., 2012 ; Kumar et al., 2021 ), reduce locomotor activity by increasing sitting and lying behaviour (Branco et al., 2020 ; Branco et al., 2021 ; Del Valle et al., 2021 ) and spread their wings from the body (Lara and Rostagno, 2013 ). They will also stay closer to the drinkers and/or to the air inlets (Akter et al., 2022 ).…”

“…Climate in the house : with high environmental temperatures, broiler chickens generally decrease their locomotor activity to avoid extra metabolic heat production (Branco et al., 2021 ; Akter et al., 2022 ).…”

“…Natural light: daylight is suggested to increase the locomotor activity (Bailie et al., 2013; de Jong and Gunnink, 2019). Climate in the house: with high environmental temperatures, broiler chickens generally decrease their locomotor activity to avoid extra metabolic heat production (Branco et al., 2021; Akter et al., 2022). …”

Severidad de miopatías de pechuga y su relación con indicadores de bienestar productivos, fisiológicos y de comportamiento en pollos de engorde

“…En días más calientes los pollos visitaron más al bebedero. Branco et al (2021) observaron secuencias de comportamiento que incluían permanecer echados más tiempo, beber y acostarse de lado en pollos bajo estrés calórico. Los pollos permanecieron poco tiempo levantados durante todo el experimento, sin embargo, no fue posible relacionar este comportamiento con la presencia de miopatías.…”

Environmental Stress in Chickens and the Potential Effectiveness of Dietary Vitamin Supplementation

“…For example, birds spend less time on eating and walking, while more time is spent on drinking, resting, and panting under HS challenge conditions (Mack et al, 2013). In a study conducted by Branco et al (2021), birds subjected to HS were prostrate, experienced shorter behavioral responses such as laying down and eating. Birds strove for adaptation under HS circumstances by increasing water intake (that helps promote heat loss), decreasing feed consumption and increasing laying down to reduce heat production through movement and increase panting to enhance evaporative cooling (Daghir, 2009;Mahmoud et al, 2015).…”