Background <p>Biosecurity measures are essential to prevent the introduction and spread of pathogens within (internal biosecurity) and between (external biosecurity) broiler farms. Implementing effective biosecurity practices not only protects animal health but also enhances productivity, welfare, and farm sustainability in general. This study assesses the temporal trends in biosecurity scores in Irish broiler farms from 2019 to 2023 using the Biocheck.UGent tool and identifies areas for improvement. The analysis includes data from 403 broiler farms, as well as recommendations provided by private veterinary practitioners (PVPs) to enhance biosecurity.</p> Results <p>The results show an overall upward trend in biosecurity scores over the study period. Internal biosecurity scores were consistently higher than external scores. Median internal scores increased from 60 (over 100) in 2019 to 75 in 2023 (<i>P</i> &lt; 0.05). External scores increased from 50 to 65 in the same period (<i>P</i> &lt; 0.05). Farms that underwent at least three assessments showed increases in median total scores of roughly 10 points after the first visit (<i>P</i> &lt; 0.05). However, certain biosecurity categories, particularly cleaning and disinfection with medians over years remaining below 70, received consistently low scores despite frequent recommendations for improvement by the PVPs.</p> Conclusions <p>The findings suggest that, while progress has been made, further efforts are needed to enhance biosecurity practices, particularly in areas with persistent low scores, such as depopulation of broilers and cleaning and disinfection. PVPs should provide more targeted recommendations for these categories and support farmers in effectively implementing these practices.</p>