Chickens can have the flu (avian influenza) and you don't even know it. Until it's too late. Chickens with a low path virus may not have many symptoms. If a high path virus is involved, you may find all your birds suddenly dead one morning.
Your best defense is to check your flock every day. Note any changes in appearance, behavior, and eating/drinking habits. Some of the signs for avian influenza include eating less, coughing, sneezing, nasal discharge, reduced egg production, lack of energy, swelling around the face, purple discoloration around the face, lack of coordination, diarrhea, muscle tremors, drooping wings, twisting of the head and neck, and inability to move. If your flock is infected with bird flu you may see one or more of these signs.
Sometimes a blood test is required to determine if the flock has been infected. Large poultry companies blood test a lot, especially their breeder flocks.
Some of the signs of bird flu are also indications of other diseases. If your chickens sneeze it does not necessarily mean they have bird flu. It is best to check with your local veterinarian.
Dr. Jacquie Jacob
University of Kentucky