For months, an outbreak of avian flu in the state’s commercial poultry flock has stopped farmers from exporting and trading their birds to some foreign counties.

Like the big hog farms, poultry farms confine thousands of animals inside huge barns. Usually owned by corporations, the birds stay long enough for contract farmers to fatten them up for slaughter.

North Carolina farmers suffered a trio of bird flu outbreaks in January, the only outbreaks to happen at commercial flocks so far this year. This aerial view shows some of the many poultry barns ...