The National Farmers' Union warned as many as 150,000 animals are under threat of being culled in the next ten days.
It said a shortage of butchers means farmers are having to 'throw pigs in a skip' because they cannot be slaughtered and carved.
Nick Allen, from the British Meat Processors Association (BMPA), told the BBC that abattoirs are unable to process pigs at the usual rate because of a shortage of workers.
This means live animals are mounting up on farms and some farmers were 'quietly starting to cull.'
Pigs are also being killed because once they grow too big, the carcass will no longer fit into supermarket packets so retailers will not buy the meat from farms.
Comment: So this man-made disaster is partly because of a shortage of workers, but also because lockdown restrictions meant that pigs were 'left packed in sheds in farms' for too long and now the number that needs butchering is well above average. This would make sense because otherwise surely a shortage of 10,000 butchers would have been an issue before now: Shipping workers warn lockdowns causing 'global transport systems COLLAPSE'
The BMPA warned there was a shortage of some 10,000 trained butchers that could lead to problems this Christmas.
One farmer said he had already been forced to slaughter hundreds of piglets due to labour shortages at his local abattoir.
The Yorkshire stockman, who has not been named, took the drastic measure because slaughterhouses were not killing them fast enough.
A friend said he had been 'destroyed' by having to 'kill perfectly healthy, viable piglets' due to the backlog.
The National Pig Association warned the UK is heading into an 'acute welfare disaster very quickly' with the country facing a 'mass cull of animals'.
Chairman Rob Mutimer said the country is just weeks away from farmers having to shoot pigs - which is legal providing it is humane and for the animals' welfare - when they run out of space.
The meat crisis is compounding woes caused by a lack of HGV drivers and fuel as well as labour shortages that will lead to a 'distinct lack of choice' this Christmas.
Minette Batters, president of the National Farmers Union, said a cull of up to 150,000 pigs was 'potentially a week, ten days away'.
She told the BBC: 'I do not feel anybody can preside over a welfare cull of healthy livestock. I don't believe it has happened in the world before and it cannot happen now.'
Comment: During lockdowns last year producers in the US were forced to dump TONS of perfectly good food because government enforced restrictions meant it was not allowed to be processed: COVID-19 lockdown = Auto-genocide? Food shortages likely as US farmers dump MOUNTAINS and LAKES of food
Ms Batters said she wants an urgent meeting with interior minister Priti Patel and immigration minister Kevin Foster. She said she has been trying to get a meeting with Patel for two years.
She said 150,000 pigs could be culled in a week unless the government issues visas to foreign butchers.
Meanwhile the Yorkshire farmer's friend told the BBC: 'He had to kill perfectly healthy, viable piglets. It's desperate. I've been producing for 26 years, and never faced the prospect of having to butcher pigs on my own farm before.'
Andrew Freemantle, a pig farmer in Exeter, Devon, said the backlog threatened farms because animals grow too big for slaughter, which hits how much they are worth.
He said his farm has not been hit yet due to its smaller size, but warned the impact on other farmers.
He told Devon Live: 'Across the industry, in Devon and the Westcountry, and the rest of the country, there are some really desperate people who are incredibly concerned about the welfare of their pigs, and their future as pig farmers.
'You can't carry on pig farming if you can't sell your pigs, if the pigs can't get into the abattoir and be processed. If you cannot sell the pigs on a regular basis, you pretty soon are ruined. There are a lot of farmers out there who are incredibly concerned that this situation will ruin them.'
Mr Mutimer from the National Pig Association echoed his woe, saying the UK is heading into an 'acute welfare disaster very quickly'.
He told BBC Radio 4's Today programme: 'The problem in the industry has got very considerably worse over the last three weeks.
'We are within a couple of weeks of actually having to consider a mass cull of animals in this country.'
He said pig farms of all sizes are running out of space to keep their animals, 'which is a real worry coming into winter'.
Asked what a culling situation would involve, he said: 'It involves either shooting pigs on farm, or taking them to an abattoir, killing the animals, and actually disposing them in the skip at the other end of the chain.
Hire low-level offenders to drive lorries amid fuel crisis, says Raab
Deputy Prime Minister Dominic Raab has suggested offenders who have been given community sentences could be used to address the country's lack of HGV drivers amid continuing concerns about fuel shortages.
Comment: Either these people are fit to drive lorries or not. If they were considered unfit before, then what makes them good to drive now? Because the government is getting desperate and is willing to risk other people's safety to cover up their mistake? Or, If, despite their sentences, they are fit to drive, then why were they suspended in the first place? Whichever way you look at it the government is exposed as being not fit for purpose.
Mr Raab, who was made Justice Secretary in Prime Minister Boris Johnson's recent ministerial reshuffle, has dismissed Labour's call for 100,000 migrant visas to be issued to provide sufficient drivers.
The former Foreign Secretary said the move would leave the country reliant in the long term on labour coming from abroad, and instead suggested the gap could be filled in another way.
'We've been getting prisoners and offenders to do volunteering and unpaid work,' Mr Raab told The Spectator, in comments carried by The Times. 'Why not if there are shortages encourage them to do paid work where there's a benefit for the economy, benefit for society?
'If you give people skin in the game, give them something to lose, if you give them some hope, they're much less likely to re-offend.'
'So these animals won't go into the food chain. They will either be rendered, or if not, sent for incineration. So it's an absolute travesty.'
Mr Mutimer said his pigs are usually around 253lbs when they go to slaughter, but are now getting up to around 309lbs.
He added: 'The pens and the sheds and everything just weren't designed for animals of this size and we're really heading into an acute welfare disaster very quickly.'
The shortage of labour in abattoirs is being blamed on the coronavirus pandemic and some point the finger at Brexit.
Comment: Except blaming Brexit doesn't fly because countries throughout Europe are also claiming that, all of a sudden, they can't deliver stock because of a 'shortage of drivers'.
Nick Allen, from the British Meat Processors Association, said the workforce in large abattoirs would normally be 10-15 per cent above average this time of year.
But he said it is 15 per cent down, meaning pigs are mounting up at farms and some farmers were 'quietly starting to cull'. They are forced into this because oversized pigs will not fit into supermarket packets.
Mr Allen said: 'The main barrier is labour, with the change in the immigration policy. We are struggling to get butchers in particular, and it limits how fast you can run the plant.
'We were offering higher wages, but with the job market at the moment, it's not worked. We do need access to some non-UK labour.'
Meanwhile the British Meat Processors Association said 1,000 EU butchers is still 14,000 short of the 15,000 the country needs.
This means businesses are focusing on keeping supermarkets stocked with simple cuts of meat such as bacon, steaks and chops.
A BMPA spokesman added: 'We really should have been producing Christmas food from about June or July onwards this year and so far we haven't, so there'll be shortages of party foods and things like pigs in blankets. Anything that is labour-intensive work could see shortages.'
Comment: If they were struggling to keep to schedule back in June and July, evidently this backlog has been growing, and July also just happens to be when other critical jobs, such as policing and healthcare, was suffering a lack of staff because of the lockdown, as well as the 'pingdemic'.
Shoppers were told this week a raft of items - from turkey to beer - are under threat this Christmas amid the supply chain crisis.
British families may also struggle to find toys and sofas or get them delivered in time for the day.
Ministers have already said they cannot guarantee that there will not be shortages this Christmas with serious problems emerging in the meat sector.
The cabinet is now said to be considering easing visa restrictions for up to 1,000 foreign butchers to avert the crisis.
But the Times claims Priti Patel is against it and concerned they are being pushed by British industry to move back towards pre-Brexit freedom of movement.
A Home Office spokesman said: 'We are closely monitoring labour supply and working with sector leaders to understand how we can best ease particular pinch points. Similar challenges are being faced by other countries around the world.
Comment: Which means that finding 1,000 - 15,000 willing butchers will not be easy.
'We want to see employers make long-term investments in the UK domestic workforce instead of relying on labour from abroad. Our Plan for Jobs is helping people across the country retrain, build new skills and get back into work.
'The Government encourages all sectors to make employment more attractive to UK domestic workers through offering training, careers options wage increases and investment.'
A spokesman for the government said that it was aware of the challenges the pig industry has faced in recent months.
They said: 'We are keeping the market under close review and continuing to work closely with the sector to explore options to address the pressures the industry is currently facing.'
The UK economy has been disrupted by several factors that have been bubbling away for months, including labour shortages, new immigration rules affecting HGV drivers and the lingering effects of the pandemic.
A spokesman for the Department For Environment, Food and Rural Affairs said that it was aware of labour shortages.
He said: 'We understand the importance of seasonal labour and we are aware of the challenges that the pig industry has faced in recent months because of the Covid-19 pandemic and labour shortages, and Defra has been working closely with the pig and processing sectors during this time.
'We are keeping the market under close review and continuing to work closely with the sector to explore options to address the pressures industry is currently facing.'
Retail analyst Clive Black of of Shore Capital also warned turkeys could be replaced by nut roasts and people will ask 'what the hell is this' when they look at their plate on Christmas Day.
It comes as drivers continue to queue for petrol amid concerns over the fuel supply chain, with industry experts fearing the problems could last for up to a month.
Business Secretary Kwasi Kwarteng admitted the fuel crisis could hit the festival season as he revealed the Government's reserve tanker fleet would be deployed.
Mr Black told the Times: 'I expect Christmas will be a nightmare for consumers. There will be food on supermarket shelves but there will be a distinct lack of choice.
Comment: And food prices across the planet are surging: Lockdowns, panic buying, low supply: Beef prices surge to unprecedented levels
'Shortages of labour have meant businesses have not laid down the same number of turkeys or planted the same number of crops and the HGV driver shortage is compounding the problem.'
Comment: Again this shows that this is partly caused by lockdowns, but, in addition, crop failures have been ongoing for many years now.
The Liverpool-based analyst added: 'A lot of people eating on Christmas Day will be asking 'What the hell is this?' It won't be traditional.
'They may be eating other meats and nut roasts. Equally if the CO2 (carbon dioxide) problem does not settle, expect beer and carbonated soft drinks to be in short supply and a lot more expensive.'
He said Christmas is 'going to be much pricier generally' and predicted that shipping issues could bring shortages of toys, bikes, sofas and electronic goods.
Mr Black also blasted David Kennedy, the director-general for food at the Department for Environment, Food and Rural Affairs, for being 'a disgrace' - and bemoaned what he described as a 'mismanagement of the economy'.
Comment: It's more than that, it's the destruction of the economy due to incompetence, greed, as well as coordinated corruption: MindMatters: How Psychopaths Infect and Destroy Hierarchies of Competence
It comes after Mr Kwarteng was asked if the fuel crisis situation would continue in the run up to Christmas, and said: 'I'm not guaranteeing anything; all I'm saying is that I think the situation is stabilising.'
On Sunday, Kate Martin, chairman of the Traditional Farm-fresh Turkey Association (TFTA), warned Britain of a shortage of Christmas turkeys amid unprecedented demand and a farm labour shortage.
She said while small farms that use local workers and sell directly to customers have been less affected, supermarket supplies are likely to be hit by a shortage of skilled European employees after Brexit.
The TFTA represents around 40 farms producing free-range birds that meet the 'Golden' turkey quality assurance mark.
It said some poultry farms have already had five times more orders this year than the same time in 2020.
Comment: The country was basically locked down for much of Christmas 2020, so it may be that there were simply less orders because people knew they wouldn't be gathering in large groups, and so the comparison to make would be 2021 with 2019? Or are we to believe that, suddenly, five times as many people want Turkey this year?
Tesco has already warned that a shortage of delivery drivers, which is causing empty shelves, could lead to panic buying in the lead-up to Christmas.
Comment: As detailed throughout the article, the shortages of numerous products is not simply due to a lack of drivers, this is because 18+ months' of lockdown have disrupted the entire supply chain.
The Government has announced a temporary visa scheme for 5,000 HGV drivers and 5,500 poultry workers brought in on three-month contracts to keep shelves stocked with turkeys and tackle fuel delivery difficulties.
Deputy Prime Minister Dominic Raab suggested offenders who have been given community sentences could be used to address the country's lack of HGV drivers amid continuing concerns about fuel shortages.
Panic buying sparked by concerns a lack of lorry drivers would prevent supplies reaching fuel pumps has brought long queues and pockets of aggression at petrol station forecourts over the last few days.
It comes as motorists say there is still not enough fuel despite The Petrol Retailers Association (PRA)'s latest survey of its members finding just over one-in-four had run dry, down from more than a third on Tuesday.
Ministers said they expected the situation to improve further, with the first troops driving tankers expected to appear on the roads 'in the next couple of days'.
Some roads around London have become gridlocked as motorists hunted for stations that have fuel, with some carrying petrol cans, plastic jugs and water bottles to stock up, and there were even reports of violence in a handful of places.
PRA executive director Gordon Balmer said forecourt staff were being subjected to a 'high level' of physical and verbal abuse from frustrated motorists.
Imminent changes to Britain's border rules could compound existing issues for freight entering the United Kingdom, a global road transport body said.
Under new immigration rules which come into force tomorrow as part of post-Brexit measures to end freedom of movement, European Union ID cards will no longer be accepted as proof of identity.
Instead, EU nationals will need a passport to enter the United Kingdom.
They said: 'We are keeping the market under close review and continuing to work closely with the sector to explore options to address the pressures the industry is currently facing.'
The words I put in bold show just how little these government servants respect the citizens they purportedly work for. The sentence says virtually nothing. The same sentence could just as well apply to the federal reserve, the shale oil "sector", banking or the DJIA.
I have come to expect this from politicians and govt. bureaucrats... this parading nothing as something.