Development agencies and animal welfare charities try to improve the health and welfare of livestock in the developing world by educating owners and providing healthcare. The impact assessment of these projects relies mainly upon input-related parameters (eg number of animals treated or educational lectures delivered). The aim of this study was to investigate whether animal-based parameters, such as scores for skin lesions, body condition and lameness, could be used to assess the impact of interventions by development agencies on working donkeys. A general checklist for integument assessment of livestock, developed and then tested on two British farms, was redefined for assessment of equine animals in West Kenya. In total, 346 donkeys were assessed over four days with a mobile clinic of the Kenyan Society for the Protection and Care of Animals, using 25 animal-based parameters. The checklist was easy to use: the parameters could be scored using visual assessment or palpation, and the procedure was completed in approximately 5 min per animal. The method was found to be acceptable for owners and animal health technicians, and no special equipment was required. Significant observations included a reduced frequency of leg lesions when head-tethering (as opposed to leg-tethering) was used, and a reduced frequency of foot lesions in regions previously visited by the charity. This animal-based method proved that the charity had made a positive impact on donkey welfare through owner education.