Smart cameras reveal how broilers respond to heat stress and ageing

Researchers monitored 1,120 Ross 308 broilers across 4 production cycles using a multi-camera tracking system capable of following bird movements from 8-40 days of age. The technology automatically measured activity levels, feeding behaviour and drinking behaviour, providing an unprecedented picture of how broiler behaviour evolves as birds grow.

The findings confirm many observations familiar to poultry farmers, while also demonstrating how automated monitoring could transform the way welfare is assessed in commercial poultry houses.

One of the clearest conclusions was that age has a major impact on activity. As broilers grew, overall movement declined significantly. High-intensity activity, such as running, started falling as early as 15 days of age and declined more rapidly than lower-intensity movements. By around 30 days of age, activity levels across all categories were noticeably lower.

According to the researchers, led by Professor Patricia Soster from the Department of Pathobiology, Pharmacology and Zoological Medicine, Faculty of Veterinary Medicine, at Ghent University, this reflects the biological reality of modern broilers. As bodyweight increases, movement becomes more physically demanding and birds naturally devote more energy to growth rather than locomotion. The results are consistent with previous research linking reduced activity in older birds to mobility challenges and poorer skeletal health.

For producers, this finding is important because activity may serve as an early warning signal. Significant deviations from expected activity patterns could indicate emerging welfare issues, including lameness, leg disorders or management problems.

Heat stress changes bird behaviour

The study also provided valuable insights into bird responses to heat stress. During periods when house temperatures reached approximately 29-30°C, birds spent significantly more time around drinkers and less time around feeders.

Overall activity levels were not significantly affected by the heat challenge. Instead of becoming dramatically less active, birds appeared to alter how they allocated their time, prioritising water consumption and reducing feeding activity.

This behavioural shift highlights a practical opportunity for poultry farmers. Monitoring drinker and feeder use may provide a more sensitive indicator of heat stress than activity levels alone. A sudden increase in drinking behaviour combined with fewer visits to feeders could serve as an early warning that birds are struggling to cope with rising temperatures.

The research also showed that behaviour followed clear daily rhythms. Activity was generally highest during the morning and middle of the day before declining later. During heat-stress periods, feeding activity was suppressed while temperatures remained elevated but increased again during the evening once conditions returned to normal.

This finding is likely to resonate with producers who frequently observe birds compensating for reduced daytime feed intake by eating later in the day. The results reinforce the value of maintaining good environmental control and providing birds with opportunities to recover after periods of heat stress.

AI enables continuous welfare monitoring

Perhaps the most significant aspect of the work is the technology itself. The system used 4 cameras combined with artificial intelligence algorithms to track birds automatically. The researchers achieved a high level of tracking accuracy despite dramatic changes in bird size over the 6-week growing period.

Unlike traditional welfare assessments, which depend on periodic manual observations, automated systems can provide continuous monitoring without disturbing the flock. This creates opportunities to identify abnormal behavioural changes long before they become apparent through production performance or mortality figures.

The researchers suggest that future precision livestock farming systems could alert farmers to potential welfare challenges, including heat stress, equipment failures, disease outbreaks and mobility problems. Sudden increases or decreases in activity, unusual feeding patterns or changes in drinker use could all provide early warnings.

There are still limitations. The work was conducted under experimental conditions at relatively low stocking densities, meaning additional validation is needed under commercial production conditions. The system also focused on only 3 behavioural measures and did not assess other welfare indicators such as dustbathing, panting or wing flapping.

Nevertheless, the study represents an important step forward in automated broiler monitoring. As poultry producers face growing pressure to demonstrate high welfare standards while maintaining efficiency, technologies capable of continuously measuring bird behaviour may become increasingly valuable.