Farmers are considered a highly important stakeholder group for the successful implementation of higher farm animal welfare (FAW) standards, but so far little is known about their attitudes and the determinants of their participation in programs that request higher FAW standards. To close this research gap, fattening pig farmers in Germany were questioned via a large-scale online survey in 2018 ( = 239). Based on the Unified Theory of Acceptance and Use of Technology, a partial least squares path modeling (PLS) was run. Results show that the expected performance as well as the expected costs associated with the Initiative Animal Welfare (IAW) substantially influence fattening pig farmers' behavioral intention to participate in the IAW. Furthermore, the decision is influenced by social determinants and facilitating conditions such as deadweight effects. Farmers' hedonic motivation, fair remuneration and previous experiences with the establishment of higher FAW standards can influence their intention to take part in the IAW. In addition, farmers' trust in the program is a major determinant. There are also moderating variables such as age and work experience that influence farmers' intention to take part in the IAW. Our results have important managerial implications for the IAW and can help to design further tailor-made animal welfare programs (AWPs) that fulfill the requirements of both fattening pig farmers and the broader public not only in Germany but the European Union.