Globally, avian influenza (AI) is a serious problem in poultry farming. Despite vaccination, the prevalence of AI in México highlights the need for new approaches to control AI and to reduce the economic losses associated with its occurrence in susceptible birds. Recombinant proteins from avian influenza virus (AIV) have been expressed in different organisms, such as plants. The present study investigated the feasibility of designing and expressing the HA protein of AIV in the transplastomic microalga Chlamydomonas reinhardtii as a novel approach for AIV control and taking advantage of culture conditions, its reproductive range, and safe use in consideration of the generally regarded as safe food ingredient regulatory classification. The results showed that the HA protein of AIV in C. reinhardtii presents antigenic activity by western blot test and through its application in chickens, demonstrating its feasibility as a recombinant antigen against AIV.