A total of 312 weaned piglets were evaluated to assess the effectiveness of Devi-Jex as a behavioural modifier and its impact on stress, welfare and growth performance. Following a 14-day adaptation period, pigs received either a standard diet or a standard diet supplemented with 0.3% Devi-Jex. Growth performance, feed efficiency, salivary cortisol concentrations and ear lesion scores were monitored throughout the trial. Pigs supplemented with Devi-Jex demonstrated a 40% reduction in cortisol levels, indicating a lower physiological response to stress, alongside reduced ear lesion scores and a reduction in stress-related behaviours. Growth performance also improved, with pigs achieving an additional 1.14kg transfer weight, a 34g/day increase in growth rate and improved feed efficiency compared to the control group. These findings demonstrate the potential of Devi-Jex as a nutritional tool to support animal welfare, reduce stress-related behaviours and enhance production performance in growing pigs.