Climate adaptation in poultry: Spatiotemporal behavioral and kinematic responses of chicken genotypes to identical temperature-humidity exposures

Climate change has increased the need to understand how different poultry types respond to heat load. This study compared the spatiotemporal activity patterns and movement dynamics of Ross 308 broilers and Ghanaian indigenous chickens under similar temperature-humidity index (THI) conditions across morning, afternoon, and evening periods. A total of 480 birds (240 per type; 4 weeks old) were housed in a semi-open system (12 pens per type; 20 birds per pen). Behavior and movement were quantified using video-based tracking and deep learning models. Mean ambient temperature (°C) was 27.5 ± 0.2 (morning, 06:00-07:00), 34.8 ± 0.9 (afternoon, 13:00-14:00), and 31.4 ± 0.9 (evening, 18:00-19:00), with relative humidity (%) of 86.7 ± 0.6, 56.0 ± 3.2, and 70.3 ± 5.3, respectively. Corresponding THI values were 79.8, 85.7, and 83.5. Genotypes differed significantly (P < 0.05). Broilers (Ross 308) spent more time resting (75.2%), with lower locomotion (4.2%). In contrast, indigenous chickens showed greater standing (39.2%) and movement (7.9% versus 4.2% in broilers). Drinking activity was higher in broilers ( P < 0.05), whereas feeding did not differ ( P > 0.05). Indigenous chickens moved faster (2.2 versus 1.9 m/s) and showed greater acceleration (1.3 versus 1.1 m/s²) than broilers ( P < 0.05), indicating higher locomotor activity. Activity levels were higher in the morning, while resting and drinking increased during afternoon and evening periods with higher THI ( P < 0.05). Significant type x time-of-day interactions were observed for all behaviors. Overall, indigenous chickens showed greater activity, movement capacity, and spatial use under heat load. These findings indicate stronger behavioral adaptability compared to broilers. Indigenous chickens demonstrate traits that can support heat tolerance. These results provide practical guidance for breeding and management strategies aimed at improving poultry performance and welfare under hot conditions.