There have been four outbreaks of highly pathogenic H5N8 avian flu in farms in central and northern Italy since the start of the month and about 865,000 chickens, ducks and turkeys will be culled, officials said on Wednesday.

The biggest outbreak was at a large egg producing farm in the province of Ferrara. The outbreak was confirmed on Oct. 6 and about 853,000 hens are due to be culled by Oct. 17, the IZSV zoological institute said.

Another outbreak involved 12,400 broiler chickens at a smaller farm in the province of Vicenza. The other two were among a small number of hens, ducks, broilers and turkeys on family farms.

In those three cases, all the birds have been culled.

The H5N8 virus led to the death or killing of millions of birds in an outbreak in western Europe last winter.