There is currently considerable interest and activity in the adoption of blockchains in food supply chains (FSC) by both researchers and industry. Blockchain developers have to satisfy the requirements of multiple users and stakeholders as well as handle technical requirements from the underlying blockchain platform. Many prior studies are conceptual and theoretical and there is a need for both a deeper understanding of the problem space and also a need for insights from real-world perspectives, particularly in the FSC context. This study interviewed 14 experts from FSC blockchain application provider companies. The interviews were analysed using a Grounded Theory approach. The preliminary findings presented in this research-in-progress paper show that developers are concerned with: Technical aspects, cost-benefit aspects, management and operational aspects, end-user issues and societal aspects. These findings provide a deeper understanding of the issues involved in developing blockchain applications in FSC.