Chlamydia psittaci is a significant and emerging disease risk to the Australian Thoroughbred breeding industry, with the potential to cause pregnancy loss in mares and pose zoonotic risks. This project investigated C. psittaci infection in mares, foals and potential avian reservoirs across multiple foaling seasons to better understand infection dynamics, risk factors and pathways of transmission. The research identified key seasonal, management and hostrelated risks and provides practical recommendations to reduce horse–bird contact, improve detection and strengthen onfarm biosecurity. These findings support improved reproductive outcomes, animal welfare and industry preparedness within the Thoroughbred Horses Program.