The virus was discovered in the Lublin province, eastern Poland, earlier this week. On Friday authorities announced that two new locations in the district have been affected.
The strain has been identified as H5N8, which is dangerous to birds but is not thought to pose a threat to humans.
The virus was initially discovered on four farms, which collectively contained 40,000 turkeys and 13,000 guinea fowl. The two new locations discovered yesterday are thought to be small scale chicken farms, with a smaller risk of further transmission.
Local officials reported that some 25,000 birds have already died at the original outbreak locations, and there are plans to liquidate a further 70,000 within the next few days to prevent further contamination.
The chief veterinarian of the Lublin province, Paweł Piotrowski, said: “We want to carry this out as rapidly as possible, and we will work over both the weekend and the Epiphany holiday.”
Soldiers of Territorial Defence Force have been assisting in clean-up operations, while the police have imposed restrictions on movement in the affected areas.
Source: PAP, Polskie Radio