Residents who keep chickens at home have been urged to be vigilant against bird flu amid fears the break out of the disease in a Norfolk back yard could have far-reaching consequences for the county's poultry sector.

Eastern Daily Press: Picture: MARK BULLIMOREPicture: MARK BULLIMORE (Image: Archant Norfolk 2015)

The H5N8 strain of avian flu was confirmed to have hit a small flock of around 35 chickens and geese in a garden in Diss on Saturday, June 3.

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Eastern Daily Press: Picture: NICK BUTCHERPicture: NICK BUTCHER (Image: �archant2016)

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That meant the Department for the Environment, Food and Rural Affairs (Defra) set up a 3km protection zone around the infected premises, along with a 10km surveillance zone, to try and stop the disease spreading.

A number of the birds have died and the remaining live birds at the premises are being humanely culled. An investigation is also underway to find the source of the infection.

But Gary Ford, chief poultry advisor for the National Farmers Union (NFU), said: 'The impact a small back yard flock can have on the commercial poultry industry can't be underestimated.'

Speaking about the latest outbreak in Diss, he said: 'It has a significant impact on the commercial poultry sector. We've taken several calls from worried members.

'It's a worrying and concerning development because it does impact significantly on their businesses.'

The main impact for commercial farms is that the surveillance zone means they have to obtain a movement licence before transporting any birds.

Mr Ford said: 'Generally, they can get a movement licence but it takes time. This is a fast-moving industry and there's going to be a delay.

'We've had this case with a small flock, but the impact on the wider region is significant as well.

'Keeping poultry at home is increasingly popular. The fact remains that a very small number of back yard poultry will have a significant impact on the wider poultry sector.'

It has a particular effect on businesses that are exporting to other countries, he said.

Many nations require that the UK is disease free in order to export, meaning that they cannot ship their goods abroad while there is an outbreak.

There are currently about 1,800 commercially-registered poultry premises in Norfolk, with around 4m chickens in the country - showing the scale of the industry and its economic value to Norfolk.

'Norfolk is a significant player in terms of poultry production,' Mr Ford said.

Mr Ford praised Defra for its proportionate response to the incident in Diss, saying both the government and the NFU consistently warned farmers about the need for biosecurity and vigilance.

'It's about attention to detail and all about keeping this dreadful virus outside the poultry shed,' he said.

But he added that: 'What goes for commercial premises goes for back yard flocks as well.

'The principles are the same - you've got to keep this disease out.'

His main warning to both commercial farmers and those keeping chickens at home is to: 'Please keep your poultry away from wild birds.

'We don't know whether that's the cause in this case, but often that's the reason.

'All of our vested interests are that this dreadful disease is contained and eliminated.'

The NFU is also distributing posters giving advice to farmers about how to prevent a break out of bird flu, saying the worst thing people can do is become complacent when there have not been any incidents for a while.

'A lot of people outside the commercial poultry sector think it's gone away,' he said.

'But this case just proves it isn't the case.'

Earlier this year 23,000 birds were slaughtered after a bird flu outbreak at a poultry farm in Redgrave.

A Defra spokesman said: 'Public Health England advises that the risk to public health from the virus is very low and the Food Standards Agency is clear that bird flu does not pose a food safety risk for UK consumers.

'Keepers are urged to continue to be vigilant and look out for the signs of avian flu in their flocks, informing the Animal and Plant Health Agency should they suspect infection.'