The epidemic of high pathogenicity avian influenza (HPAI) H5N1 in the United Kingdom and Northern Europe from 2021-2023 has dwarfed all previous incursions. This fact has driven the need to review biosecurity behaviours and perceptions of virus incursions on commercial poultry farms. This study used qualitative methods to evaluate farm managers’ perceptions of biosecurity and their implementation of measures as recommended by the Animal and Plant Health Agency (APHA). Thirteen farm managers across different regions of England and Wales were recruited between May and September 2023 to take part in the study. Qualitative semi-structured interviews were held with managers to discuss various topics relating to biosecurity and avian influenza (AI). Biosecurity measures being used across the farm by managers and staff were also observed to help understand biosecurity behaviours. Interviews were transcribed and analysed to identify themes and patterns amongst the data, along with extensive notes collated during the farm visits. Findings showed that farms’ use of biosecurity with respect to disinfection regimes and use of foot dips were both well cited and observed. Similarly, farm managers were all highly likely to refer to the use of farm-specific and shed-specificrubber boots, while also citing stricter requirements for visitors and delivery/maintenance. Biosecurity concerning the layout of the premises, fencing, access to changing rooms and the general age and maintenance of buildings and sheds required significant improvement across many farms. Additionally, farm managers expressed strong feelings of stress and anxiety in recent years, particularly those who had experienced an AI outbreak recently. We argue that factors such as risk perceptions, remits of control, feelings of responsibility and autonomy, and consequences on mental health, are all factors that can inform how farm managers respond to outbreaks and implement or sustain biosecurity on farms. A greater emphasis on providing regular and tailored training and educational resources for the industry would be beneficial as would further services focusing on reducing the burden on farmers’ mental health. This research provides insight into the application and shortcomings of biosecurity implementation on commercial poultry farms. It also identifies farmer perceptions and experiences shaping implementation on farms. However, this highlights that the onus for improving biosecurity cannot remain solely with farm managers and workers. Further research exploring the role of other stakeholders in the industry would help bridge remaining gaps in our understanding of biosecurity implementation.