Tail lesions caused by tail-biting of conspecifics are a welfare concern in pig production. A recent study found a prevalence of 39.7% in Swiss slaughter pigs. Tail-biting is a multifactorial problem and farmers have to alter housing conditions and/or management procedures to reduce the occurrence of this behaviour. To obtain information on intervention measures, farmers may ask consultants (e.g. veterinarians) for advice or use information provided online. This study aims to elaborate the most efficient way of implementing intervention measures by examining the efficiency and feasibility of personalised advice in comparison to online information. The preva-lence of tail lesions in fattening pigs will be assessed at beginning, middle, and end of 2 batches on 75 Swiss farms allocated to 3 cohorts. Farmers receive either personalised advice, support in using online information (advisory tools), or no information. Moreover, the effectiveness of different intervention measures is quantified. Results will be disseminated to Swiss pig produc-ers.