Avian leukosis virus (ALV) is a retrovirus that primarily affects birds, particularly domestic chickens. It can lead to various diseases, including tumors and immunosuppression, impacting the health and productivity of poultry. ALV is transmitted through direct contact, contaminated equipment, or infected eggs. There are several subtypes of ALV, each associated with different clinical outcomes. Vaccination and biosecurity measures are essential for controlling the spread of this virus in poultry farms. Understanding ALV is crucial for poultry producers to maintain flock health and ensure food safety in the poultry industry.