An outbreak of avian influenza on a chicken farm in southern Bulgaria has led to the flocks there being culled, the country's food safety agency said on Friday.

The industrial farm in the village of Bogdanitsa is the seventh to be hit by the highly pathogenic avian influenza type A in the southern part of the Balkan country since December, reported Reuters.

The risk to humans from the disease is considered to be low, but past outbreaks among farm birds have resulted in extensive slaughtering programmes to contain the spread.