Migratory birds on their journeys in October (north-south) and March (South-North direction) transmits along their route various microorganisms in particular: wild virus infectious bronchitis and Haemophilus gallinarum. Both microorganisms produce pathologies that occur with respiratory symptoms that start in the upper respiratory tract. Other organs such as kidney and oviduct (infectious bronchitis virus) or lungs (in case of Haemophilus) can be affected later. In the photo you may observe a case of hydrosalpingitis of the right oviduct in female broiler.