Animal welfare assessment systems are mainly used by external auditors. Better commitment could be achieved if farmers could assess the welfare of their pigs themselves and act to improve it. A project was designed to build an animal welfare assessment tool with farmers from three different French regions. An exhaustive list of criteria was established at three co-design workshops involving farmers, their advisers and animal welfare experts. Farmers indicated how they evaluated whether their animals were doing well, either spontaneously in a brainstorming discussion, or by answering to questions from a naïve visitor. Then representatives of the groups gathered, prioritized and selected the criteria according to four dimensions: housing (cleanliness, moisture, resting posture), behaviour (fear of human, use of enrichment material), health (diarrhoea, coughing, lameness, severe body/tail lesions, physical appearance) and feeding (trough/drinker cleanliness, low body weight). They proposed rapid measurement methods (observation at group level from the corridor and individually in the pen) and stages to use them: two rooms in the post weaning period (PW) and two rooms in the growingfinishing period (G). A prototype tool was built on these bases. Farmers and advisers scored their animals twice, after the training session and six months later (spring 2017). The first series of evaluation indicated that lameness frequency was lower in PW than in G (0.27 vs 0.41% of pigs) and ranged from 0 to 1.7% (PW) and 3.6% (G). Exploratory behaviour was scored when entering the room and 10 minutes later. The percentage of pens with enrichment investigation was higher after 10 minutes presence, higher in PW period than in G period (34.5 vs 23.1%) and ranged from 0 to 100% of pens. The feedback of both sessions will allow to assess the feasibility of this tool in different type of farms, the difficulties encountered in the implementation by the farmers and to finalize with them a list of relevant measures.