is the leading cause of food poisoning in the UK. 2 Sisters Food Group, with retail partners, monitored the effect that: (1) awarding financial incentives to farmers and stockpersons for producing houses that were not highly contaminated with , or (2) the cessation of thinning (where ~30 per cent of birds are removed and processed at around day 35 of the crop cycle), had on prevalence of on UK broiler farms in a longitudinal monitoring study. Ninety-four farms and 759 houses were monitored from November 2013 to October 2015, with and without interventions. Financial incentives and thinning were significantly associated with prevalence. Houses on farms receiving an incentive had a 54 per cent reduction in odds of being highly contaminated with Houses that were thinned had a 309 per cent increase in odds of being highly contaminated. Temperature and bird age were significantly positively associated with Changes in industry practice at supply chain level can support control plans in commercial broiler flocks. Elucidating farm-level factors associated with prevalence (such as house type, condition, flock size) as well as individual factors related to thinning (stocking density, weight profile and associated economic consequences) require further investigation.