Behavioral patterns in broiler chickens monitored with a multi-view tracking system

Understanding behavioral changes across the production cycle is essential for broiler welfare assessment. This study monitored three key broiler chicken behaviors over time: activity level (based on net displacement per second) and time spent at the feeder and drinker zones. It includes the analysis of activity dynamics (high, medium, and low activity level), distance traveled over time, the effect of time of day (morning: 9:00-12:00, midday: 13:00-16:00, and evening: 18:00-21:00) on behaviors, and behavior during periods of experimentally induced high environmental temperature (29,4 ± 1°C; from days 29 to 33 and 36 to 40). This study involved four production rounds, each with 280 as hatched Ross 308 broilers (1,120 total), housed in two climate-controlled pens (9×4 m) per round (140 birds/pen; 14 kg/m²). A multi-camera system tracked broilers using a YOLOv11 model and the SORT algorithm. Tracklets (short segments of a moving object's trajectory) were projected onto ground-plane coordinates and merged across views to form unified movement paths. The system achieved high tracking accuracy (MOTA: 0.81; IDF1: 0.89). Video segments (n=1,641) of 3 minutes each were recorded between days 8 to 40. Broiler behaviors from 8 to 40 days of age were significantly influenced by high environmental temperature and age. Heat exposure increased time spent at the drinker and reduced time spent at the feeder zone, while overall activity levels were unaffected. Activity dynamics shifted across the production cycle, with high-intensity activity decreasing earlier and more rapidly than medium and low activity, leading to a progressive dominance of lower activity levels as broilers aged. Behavioral patterns also varied by time of day, with time at feeder zone and activity partially rebounding in the evening after the heat-challenge period. While the system offers valuable monitoring insights, it has only been tested under controlled conditions with low density, and validation under commercial conditions is still needed.