Farmers said more must be done to prevent bird flu spreading from back-yard poultry flocks, amid fears the latest outbreak could have consequences for East Anglia's valuable commercial poultry sector.

The H5N8 strain of avian flu was confirmed in a small flock of around 35 chickens and geese in a domestic back garden near Scole, outside Diss, on Saturday – the third case in the area this year.

Surviving birds at the premises were humanely culled and an investigation is under way to find the source of the infection.

Defra also set up a 3km protection zone around the infected premises, along with a 10km surveillance zone, to stop the disease spreading.

But Gary Ford, chief poultry advisor for the National Farmers Union (NFU), said domestic keepers needed to be equally aware of prevention measures and restrictions, and to keep their poultry away from wild birds which presented the main risk of infection.

'The impact a small back yard flock can have on the commercial poultry industry can't be underestimated,' he said.

One of the farmers within the new 10km surveillance zone is Alastaire Brice, of Havensfield Happy Hens in Hoxne, whose chickens must be kept indoors under restrictions which also mean he needs a licence to move birds or eggs off his farms.

'We have locked our birds inside, but I am driving around and seeing so many chickens walking around in the countryside – it infuriates me,' he said.

'We will never get insurance now on avian influenza when we have professional keepers surrounded by hobby keepers who are not aware of the repercussions of this.

'It is bad luck if they get it (bird flu), and you can't blame anyone for getting it, but they have to apply the same rules and regulations as we do.

'It does not matter if it is 25 birds or 25,000. The disease is present and anyone in the vicinity is at risk from it.'

Mr Brice said Defra needed to do more to engage with domestic keepers who were not commercially registered and 'not on their radar'.

'This is my livelihood, but I have not had a Defra or animal health official contact me yet,' he said. 'If I'm not getting a phone call, then those hobby keepers definitely won't be.

'They are ignorant to all this, and I don't mean that in a nasty way. They are not going to look at government websites if they are working during the daytime. I phoned two people up in Scole and they didn't have a clue.

'You would have thought Defra would have sent surveillance teams out or put up signs in the area to say there is a bird flu outbreak and you must keep your birds locked up. They have got to engage with these people.'

GOVERNMENT RESPONSE

A Defra spokesman said there had been an 'ongoing communication campaign' to reach back-yard poultry keepers during the recent outbreaks, and there would be door-to-door patrols carried out by local councils within the surveillance zone to identify and advise flock owners.

'Disease outbreaks cause birds to suffer, damage businesses and cost UK taxpayers millions – it is important all poultry keepers take action to protect their birds,' she said.

'We keep poultry keepers informed through clear, simple online guidance, door-to-door advice in affected areas, local and national media, email alerts, a telephone helpline and by working with local vets and the poultry industry.'

The government's chief vet has also issued advice for people with backyard poultry on how to limit the risk to their birds by complying with the prevention order which legally requires them to keep birds separate from wild birds and practicing good biosecurity.

Saturday's outbreak was the third case in the area this year, after 23,000 birds were culled at a farm in the village of Redgrave in February, and a further 55,000 birds culled after the virus was identified at a nearby duck unit.

Public Health England advises that the risk to public health from the virus is very low and the Food Standards Agency says bird flu does not pose a food safety risk for UK consumers.

For more information and advice on bird flu prevention and restrictions, click here.