Greece has reported an outbreak of the highly contagious H5N8 bird flu virus among laying hens on a farm in the southern part of the country, the World Organisation for Animal Health (OIE) said on Thursday, citing a report from the Greek farm ministry.

The country had already reported a case of H5N8 in a swan in December but this would be the first outbreak on a farm.

Some 28,000 hens died of the virus, the report said.

The H5N8 Bird flu virus has spread among European countries in recent months with more than 20 countries hit so far, according to the OIE.