This paper describes a case example where initiatives from private assurance schemes, scientists, charities, government and egg companies have improved the welfare of UK cage-free laying hens. The RSPCA and Soil Association farm assurance schemes introduced formal welfare outcome assessment into their annual audits of laying-hen farms in 2011. Feather loss was assessed on 50 birds from each flock on a three-point scale for two body regions: Head and Neck (HN) and Back and Vent (BV). In support of the observations, assessors were trained in feedback techniques designed to encourage change in farmer behaviour to improve welfare. In addition, during Year 2 farmers were asked about changes they had made, and intended to make on their farms. During 2011-2013 there were also wider industry initiatives to improve feather cover. Data were analysed from 830 and 743 farms in Year 1 and Year 2, respectively. From Year 1 to Year 2 there was a significant reduction in the prevalence of feather loss from 31.8% (9.6% severe) to 20.8% (6% severe) for the HN region, and from 33.1% (12.6% severe) to 22.7% (8.3% severe) for BV. Fifty-nine percent of 662 farmers reported they had made changes on their farms during Year 1 to improve bird welfare. For such a substantial industry change, attributing causation to specific initiatives is difficult; however, this is the first study to demonstrate the value to animal welfare of certification schemes monitoring the effectiveness of their own and other industry-led interventions to guide future policy.