Masked workers hold chicken with bird flu©Rex Shutterstock

Defra is investigating a suspected case of H7 avian influenza in Lancashire following a marked increase in bird mortality at a combined free-range and colony site.

The unit, owned by producer/packer Staveley’s Eggs, is located just to the north-east of Preston, where a 10km temporary control zone has been set up, imposing stringent movement restrictions on poultry and other animals.

The site is home to about 120,000-colony cage layers and another 50,000 free-range layers. Mortality in the free-range flock is said to have reached about 20%, and 5% in the caged birds.

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Defra has sent an official sample to Weybridge and is awaiting the results.

The birds are due to be culled on Saturday on suspicion of avian influenza.

A compliance officer for Staveley’s said the company was currently working with government officials, but the outbreak appeared to be limited to one site.

If confirmed, a 3km protection zone and a 10km surveillance zone will be established, restricting all livestock movements in the short term.

map of Lancs avian flu outbreak

There is believed to be a considerable number of other poultry units in the area, as Lancashire was traditionally a poultry dense part of the country.

“The decision to take precautionary action has been based on the clinical symptoms displayed by birds at the farm and emerging laboratory findings,” said a Defra spokesman. “The investigation into the suspect case and laboratory tests are ongoing.”

The Scottish Egg Producer Retailers Association has urged all egg producers to step up their biosecurity and stop all unnecessary visits.

A number of local producers have already housed their birds as a precaution.