Avibacterium paragallinarum (A. paragallinarum) is one of the primary pathogens causing respiratory diseases in poultry flocks, posing a serious threat to the health and production efficiency of the global poultry industry. With the expansion of modern farming scales and changes in environmental factors, mixed infections involving A. paragallinarum alongside other bacteria and viruses have become increasingly prevalent. This has led to more complex and diverse disease manifestations, significant