Two new outbreaks of avian influenza have been confirmed in poultry in Orkney and in North Yorkshire, the government has confirmed.
Avian influenza of the H5N8 subtype was found on Thursday (17 December) in a small commercial free range laying flock on Sanday, Orkney.
Temporary Control Zones (TCZs) of 3 km and 10 km have been put in place, the Scottish government explained.
The TCZs are temporary and will remain in place until the pathogenicity of the virus is identified.
The zones place movement restrictions on poultry, carcasses, eggs and other things liable to spread disease.
In a separate outbreak on Thursday, avian influenza of the H5N1 subtype was confirmed in a backyard flock of chickens near Hawes, in North Yorkshire.
A 3km and 10km Temporary Control Zone and a 10km Temporary Movement Restriction Zone have been declared around the premises, Defra said.
Further testing and genetic sequencing is underway to confirm the pathogenicity and to confirm that it is also the same H5N1 strain previously found in wild birds.
The area has very few poultry premise with the GBPR listing just 14 premises in the 10km controlled zone, Defra added.
The new outbreaks come as two other cases were recorded in the past week - a highly-pathogenic strain in Derbyshire on Tuesday and a case in captive birds at a non-poultry premises in Worcestershire on 13 December.
The increasing number of cases comes as mandatory housing measures were rolled out across the country from the start of this week.
It is now a legal requirement for all farmers and poultry keepers to keep their birds indoors following a string of outbreaks.
They will need to follow strict biosecurity measures to limit the spread of avian influenza and eradicate the disease.
The risk of incursion of bird flu is 'very high' for wild birds, and 'medium' for poultry with high biosecurity and 'high' for poultry with poor biosecurity.
A joint statement from Britain’s three Chief Veterinary Officers (CVOs) said: "Whether you keep just a few birds or thousands, from 14 December onwards you will be legally required to keep your birds indoors.
"We have not taken this decision lightly, but it is the best way to protect your birds from this highly infectious disease."
How can I prevent bird flu?
Keepers are advised by Defra to be vigilant for any signs of disease in their birds and any wild birds, and seek prompt advice from their vet if they have any concerns.
They can help prevent avian flu by maintaining good biosecurity on their premises, including:
• Housing or netting all poultry and captive birds
• Cleansing and disinfecting clothing, footwear, equipment and vehicles before and after contact with poultry and captive birds
• Reducing the movement of people, vehicles or equipment to and from areas where poultry and captive birds are kept
• Thoroughly cleaning and disinfecting housing at the end of a production cycle
• Keeping fresh disinfectant at the right concentration at all points where people should use it, such as farm entrances
• Minimising direct and indirect contact between poultry and captive birds and wild birds, including making sure all feed and water is not accessible to wild birds