In poultry production, not all diseases appear in a severe or dramatic form. Some viruses enter the flock quietly, yet their economic impact can be substantial.

Avian influenza subtype H9 is considered one of the most significant poultry diseases. Although it is not typically associated with high mortality rates, it is highly important economically because of its ability to suppress the immune system and predispose birds to secondary viral or bacterial infections. Its primary impact is economic, leading to:

• Weight loss and reduced growth performance
• Increased medication costs
• Poor response to vaccination programs

Prevention is the First Line of Defense

• To control H9, a strong and appropriate vaccination program must be implemented.
• Strict adherence to biosecurity measures is essential.
• Regular laboratory monitoring of the flock is necessary for early detection.