Controversial plans to build a megafarm with up to 870,000 chickens and 14,000 pigs between two villages have attracted nearly 15,000 complaints.

Cranswick, the food giant behind the plans, says the two sites will be set 400 yards apart and operate separately to act as a ‘bio-precaution’.

But locals fear the giant facility will belch out foul odours including ammonia fumes, attract swarms of flies and result in thousands of lorries driving past homes.

The strength of public opinion emerged as the local planning authority revealed it had received the ‘highly unusual’ amount of objections.

So far, the Borough Council of King’s Lynn and West Norfolk has received 13,362 letters from residents in an around Methwold and Feltwell and campaigners opposed to the scheme, plus 1,445 comments through its planning portal.

Just eight people have written in support of the plans.

By comparison, an application by a developer to build up to 4,000 homes in West Winch – dwarfing the existing population of fewer than 3,000 people – has generated just 144 objections and a petition signed by 32 people.

Objections to the megafarm include one that says: ‘This cannot be allowed. It will destroy our countryside with pollution in the rivers, earth and air.

‘Stench will be appalling. Disease will be rife… Welfare of animals is not good either.

‘Tourists will stop coming to the area due to smell and pollution. House prices in outlying villages and towns will plummet…

‘We will no longer be able to enjoy our gardens or countryside, won’t be able to hang out washing or have barbecues.

‘There is also the added chaos the lorries will cause on our already congested roads and small, narrow lanes.’

Another wrote: ‘This type of factory farm is completely unnecessary, with very low standards of animal welfare, and will impact enormously on the local roads.’

Another complained: ‘This is an area of outstanding natural beauty with SSSIs (Sites of Special Scientific Interest), SPAs (Special Protection Areas) and SACs (Special Areas of Conservation) and attracts holidaymakers bringing investment to the region.

‘This would be damaged if tourists could not bear the smell and ammonia-related reactions that come with these factories.

‘The ability to wild swim in the rivers [would be affected] due to the pollution from both the factory and from the runoff from spreading on local farms.’

In a further blow to Cranswick, campaigning groups Feedback and Sustain claim the two applications for the separate megafarm sites are ‘unlawful’ because they fail to provide details of expected greenhouse gas emissions, preventing a proper assessment on ‘climate change grounds’.

The organisations – which have threatened legal action if the applications are approved despite their ‘significant deficiencies’ – claim the megafarm and associated suppliers would generate the equivalent of 120,000 tonnes of CO2 every year, or nearly a third of the amount already produced by all road traffic in the borough annually.

Phil Holtam, programmes manager at Feedback, said: ‘It’s absolutely right that so many are concerned and raising their concerns directly with the council.

‘Not only will the megafarm lead to local impact in terms of air and water quality, waste, odour and traffic, but there will be inevitable and significant climate harm from the massive volumes of feed required to rear many thousands of animals.’

Ruth Westcott of Sustain, which campaigns for better food and farming, said: ‘The scale of objection to this megafarm has been overwhelming.

‘One reason for concern is that key information is missing from the planning documents, meaning we don’t know fully what the environmental impact could be.

‘This megafarm simply shouldn’t go ahead. Sustainable farming is the real path to good local jobs and decent returns for farmers.’

Cranswick, a pork and chicken producer which supplies meat to major supermarkets, submitted its plans for the former World War II airfield in April.

Under the proposals, a broiler unit for chickens will have 20 sheds, each measuring 320ft by 79ft, with enough floor space to hold 43,500 birds at a time and produce six million per year.

The birds will be hatched in the sheds from eggs which have been laid at nearby farms. They will be transported to Cranswick’s plant in Eye, Suffolk, for processing when they are seven weeks old.

The pigs would be housed in 14 sheds measuring 230ft by 49ft, each one holding 1,000 animals and capable of producing 56,000 annually.

The ‘finishing unit’ where pigs that have been reared outdoors will be brought when they are 12 weeks old and weigh around 77lbs.

They will stay indoors for another 12 weeks until they reach their target weight of around 240lbs and are ready to be slaughtered.

Cranswick states in its planning application that the sites would cause ‘negligible disturbance’ to nearby wildlife havens.

But local campaigners Cranswick Objection Group have described it as a ‘monstrosity right on our doorstep’ and an ‘overwhelming catastrophe that could destroy our homes, our health and our landscape’.

The group stated: ‘Not only will the stench, the noise and the swarms of flies be sickening but the additional HGV traffic on country roads will turn a simple journey for us into an absolute nightmare.’

Other objectors include the World Wide Fund for Nature, which warns the environmental impact of the farming complex has not been properly assessed.

Villagers living near a much smaller Cranswick chicken plant in Westhall, near Halesworth in Suffolk, have complained of being plagued by flies for the last two summers.

And locals in Stow Bedon, Norfolk, have claimed they have suffered nose bleeds, headaches, breathing problems and spoiled food due to the stench of ammonia from a Cranswick pig farm.

Cranswick has said previously it was aware of complaints and was ‘working closely with the EA on this matter’, and that the EA has confirmed it operated within the parameters of the relevant permit relating to the local environment.

Their previous statement read: ‘After construction, the requirements for the operating permit changed and, in dialogue with the EA and local authority, the changes were implemented.

‘We continue to work closely with the EA who confirm we operate within the agreed parameters of the permit relating to the local environment.’

The poultry farm at the Methwold site would be built by Cranswick subsidiary Crown Chicken on an area of farmland containing a series of run-down poultry huts which have not been used for many years and will be demolished.

The pigs will be housed by another Cranswick subsidiary, Wayland Farms, in ‘high-quality, purpose-built’ units, replacing a range of existing run-down buildings.

The current site has a capacity for 37,500 pigs, although it has been operating at 20 per cent capacity with only 7,500 piglets due to the poor condition of the existing buildings.

A Cranswick spokesman said: ‘We have considered the extent to which the full analysis of GHG (greenhouse gas) emissions were required for this planning application and are satisfied that all of the necessary information has been included.’

King’s Lynn and West Norfolk, which campaigners say failed to request the climate change impact for the planning applications, said a 30-day consultation would take place this year, with the planning committee making a decision ‘early next year’.

A spokeswoman said of the number of objections: ‘It’s highly unusual [but] this is really difficult to compare [to other schemes] because it’s a different type of planning application.’