A fourth Victorian chicken farm has been struck down with avian influenza with all birds set to be culled.
Tests confirmed the highly pathogenic H7N3 strain of bird flu at the farm located within the Golden Plains Shire in Victoria's southwest, Agriculture Victoria confirmed on Wednesday.
The farm is situated within a current restricted area which covers two other poultry and farms in Meredith and Lethbridge after both also tested positive for the same strain in the past few weeks.
Authorities have placed the latest farm into quarantine and all poultry will be disposed of and the sites cleaned and cleared of the infection.
Another farm in Terang, about 130km from the Meredith farm which is both owned by one operator, had also tested positive to another strain of the flu.
About 500,000 birds were euthanised at the Meredith and Terang farms, operated by Avgo and Surf Coast Eggs Farms, and share management, staff and machinery across sites.
The Lethbridge farm, operated by Farm Pride, culled about 80,000 hens, representing eight per cent of the company's total production capacity.
Victoria's Chief Veterinary Officer Graeme Cooke said this detection is not unexpected and is the result of comprehensive and ongoing surveillance activities.
"We remind bird owners that housing birds, where practical, is an effective method of minimising direct contact with wild birds," Dr Cooke said.
Movement restrictions remain in place for the designated areas near Terang while the control areas around Meredith have been extended to include Bacchus Marsh Road in the east and the Colac-Ballarat Road on the western boundary.
Bird keepers located in restricted and control areas in Meredith and Terang have been ordered to keep their birds enclosed in cages and sheds as much as practical.
Consumers should not be concerned about eggs and poultry products from the supermarkets, they do not pose a risk and are safe to consume.
The US has placed restrictions on imports of Victorian poultry and poultry by-products until further notice.
