High numbers of migrating birds could be putting parts of Cumbria at risk of an outbreak of a dangerous strain of bird flu.

The Solway Firth is home to thousands of migrating birds over the winter, and according to a county union chief, because of this poultry farmers should heed an order to bring their birds indoors to protect against a strain of bird flu responsible for thousands of turkeys, chickens and geese being culled in Europe.

"It all hinges around migrating birds bringing in this strain of bird flu. We have as many migrating birds here in Cumbria as anywhere. Just take the Solway Firth, where we see huge numbers of Barnacle Geese make their home every winter," said National Farmers Union Cumbrian council delegate, Alistair Mackintosh.

"Because of this it is vital that stocksmen bring their poultry inside, but it is going to be a challenge. It is going to take more time and effort to maintain when they are inside sheds or barns," said Mr Mackintosh, a west Cumbrian farmer.

"I have a few chickens that are free-range, but I brought them inside immediately the order was put out," he added.

Defra chief vet Nigel Gibbens declared a "prevention zone" from yesterday for England, with requirements for commercial and individual poultry and captive bird keepers to keep their birds inside, or take "appropriate steps to keep them separate from wild birds".

This order to bring in the birds will last for at least 30 days.

Outbreaks of the H5N8 strain of bird flu have been confirmed on farms in France, Germany and Sweden, and fears are building it could come to the UK.

There have been no cases of the strain infecting humans, and Public Health England (PHE) advises that the threat to human health remains very low.

Prof Gibbens said Defra had increased its surveillance for the disease, and keepers are being urged to reinforce biosecurity measures.

"Even when birds are housed a risk of infection remains so this must be coupled with good biosecurity – for example disinfecting clothing and equipment, reducing poultry movement and minimising contact between poultry and wild birds," he said.

Mr Mackintosh said the restrictions, although falling during the busy festive period, could have been worse if they had been introduced earlier.

"The only saving grace is that it didn’t happen two weeks ago," he said. "We started preparing our Christmas birds in November and we are about two-thirds through our campaign, so we have probably only got a week’s worth of production to do. If this had happened a week later it would have been better, but if it had happened two weeks ago it would have been a disaster.

"These birds have been outside since the summer, and most of them will be processed and safe in a cold store by now. It is not as bad as it could have been."

Local auction marts say the bird flu warning will not affect the seasonal sale of hundreds of turkeys, geese and chickens later this month.

"Our sale on December 21 will still be going ahead. This outbreak in Europe will not stop sellers from bringing their rough-plucked and dressed birds to be auctioned off," said Heather Pritchard from Harrison & Hetherington at Rosehill in Carlisle.