The topic of integration and development of sustainable chains has lately gained much attention in the academia debates. In particular, how to manage integration in the bio-energy chains is discussed. Integration is a process of progressive dependence among different actors willing to coordinate processes of innovation. This dynamic is generated by the interaction of individuals willing to start up collective action. The effectiveness of a collective action depends on the number of formal norms developed by collective contracts. This paper tackles these issues considering the specific case study of a collective action in a bio-energy chain. It focuses on the decision-making process of farmers on whether to join or not a collective action, analysing their trade-offs over the attributes of collective contracts. The empirical study was conducted in an area in Southern Italy, most affected by soil erosion problems. A stated preference model was implemented where respondents were asked to choose between alternative collective contracts with varying attribute levels to start biomass cultivation. Two hundreds face-to-face questionnaires were administered to farmers in September-October 2013. First results show that participation is mainly influenced by minimum price guaranteed, contract length, and re-negotiation before the end of a contract.