Undercover footage has revealed multiple sheep getting trapped in a conveyor belt at a Welsh slaughterhouse that is already under investigation for mistreating animals.

The alarming footage taken at Farmers Fresh abattoir in Wrexham, North Wales, shows two live sheep struggling under the weight of a dead animal as they made their way along the conveyer belt to be slaughtered.

Images show several sheep getting their heads and limbs stuck in the conveyor belt, while graphic footage seen by MailOnline, which is too shocking to be shown, shows a sheep being stunned and having its throat cut after being trapped.

Pictures taken at the abattoir, which is supposedly 'under investigation', also shows sheep carcasses lying on the slaughterhouse floor, having died from unknown causes.

Animal Equality UK accused the slaughterhouse of causing the sheep unnecessary suffering, a breach of the UK's strict slaughter controls, and called on the FSA to take 'immediate action'.

The RSPCA has stated that it has 'concerns' about the footage, and has called for anyone with information to come forward 'as a matter of urgency'.

Shocking footage showed a dead sheep being placed on top of two living animals at the slaughterhouse in Wrexham, Wales, that is already under investigation

When one sheep became stuck in a conveyor belt, the harrowing footage also showed it being stunned and having its throat slit

The alleged mistreatment was filmed by animal rights group Animal Equality UK between July and August, less than a month after an Animal Aid investigation, revealed exclusively by MailOnline, caught footage of sheep being trampled and thrown onto their backs at the same abattoir and forced the FSA to take action.

It is expected to re-ignite calls for CCTV to become compulsory in Welsh slaughterhouses. It is is already required in England and Scotland.

Acting Executive Director of Animal Equality UK, Abigail Penny, said: 'These defenceless animals are treated like commodities, placed on a conveyor that delivers them to their death.

'Slaughterhouses are inherently unforgiving places and this systematic neglect – made all the worse by poorly designed equipment – causes even more distress for these terrified lambs and sheep.

Footage also showed sheep being stunned in the eyes (pictured). After viewing the footage, the RSPCA said it had 'concerns' about the slaughterhouse

Animal Equality UK, which captured the images between July and August following an Animal Aid investigation, also caught these images of sheep hanging out of a conveyor belt

'We demand justice for these vulnerable animals. The Food Standards Agency must take immediate action against Farmers Fresh Wales and their own officer who failed in his duties.

'If people want to stop supporting the suffering that takes place in slaughterhouses, it has never been easier to choose plant-based options instead of meat.'

After the RSPCA's welfare specialists viewed the footage, they said they had 'some concerns'.

'We would like to be able to look into it further,' they said.

'The welfare of animals must be the first priority. We would urge anyone with further information or concerns about this slaughterhouse to report this to us as a matter of urgency.'

In a statement, the FSA said it would begin an investigation the footage, alongside its current investigation, which is expected to take months to complete.

'The Food Standards Agency takes animal welfare at slaughterhouses very seriously,' said a spokesman.

'An investigation is already underway at the business and we are examining this new evidence closely.

'We are unable to comment further while the investigation is ongoing.'

A dead sheep was also photographed on the slaughterhouse floor by animal rights activists

This sheep is pictured shortly before it is stunned before slaughter. An Animal Aid investigation sparked the slaughterhouse regulator to start investigating this abattoir

After viewing the footage, an Animal Aid spokesman said they were 'deeply concerned' by the findings and called for 'urgent questions' to be asked about the effectiveness of the current regulator.

'We believe that urgent questions need to be asked about the current regulatory regime, and whether it is fit for purpose,' they said.

'If those tasked with enforcing the law are allowing such terrible suffering to be inflicted on vulnerable animals, then that is absolutely unforgivable, and they must be held to account.

'The chaos, brutality and incompetence uncovered by Animal Aid’s earlier investigation were bad enough.

'It is absolutely unthinkable that nightmarish scenes should have been filmed at the slaughterhouse yet again, after we had reported our investigation to the Food Standards Agency (FSA), and they had assured us that robust action was being taken.'

And in a statement the Royal College of Veterinary Surgeons, the UK's vet regulator, said it did not comment on individual cases, but would be able to consider the case 'in line with our normal concerns investigation process'.

It follows a poll taken by the animal rights charity, which found that 79 per cent of Welsh people backed making CCTV a legal requirement in slaughterhouses.

Just 4 per cent of respondents said they would oppose the move.

The cameras would help protect animals from additional abuse when they go to slaughter.

Sheep were also photographed in the conveyor belt as they went up to slaughter

And one animal was shown with its head sticking out of the bottom of the conveyor belt as it headed up the ramp to slaughter

Joyce Watson, an assembly minister for the National Assembly for Wales' Climate Change, Environment and Rural Affairs committee said that the country should not 'turn a blind eye to the horrific cruelty that goes on behind closed doors'.

'Until CCTV is compulsory in all our abattoirs – and Official Veterinarians given unrestricted access to the footage – we cannot ensure animals in Wales are properly handled and cared for at the end of their lives', she told MailOnline.

'We must take action now.'

Footage from between March and June this year, captured by Animal Aid, showed sheep hiding in the corner as workers dragged them by the legs and neck onto a conveyor belt, and sat on them to stop them escaping.

Sheep were also seen being stunned repeatedly on the head and legs.

A hidden camera at a slaughterhouse in Wales, in place between March and June this year, caught sheep being hurled onto their backs, trampled and improperly stunned moments before their death at a Welsh slaughterhouse

The harrowing footage, released exclusively by MailOnline last month, was filmed by Animal Aid activists investigating Farmers Fresh abattoir in Wrexham, Wales. (Pictured: A worker grabs a sheep by the neck before hurling it onto the conveyor belt)

Animal Aid's campaign manager Tor Bailey accused the abattoir of 'numerous failings'.

After viewing the footage, a spokesman for the FSA said they have staff at the slaughterhouse permanently to monitor animal welfare and have introduced additional welfare checks.

'We took swift action to increase our presence at Farmer Fresh in Wrexham and to introduce additional checks and ensure animal welfare was being protected.

'We take animal welfare at slaughterhouses very seriously and a criminal investigation is underway.'

The slaughterhouse was rated as 'requires improvement' in its most recent inspection, published at the beginning of August, carried out by the Food Standards Agency.

Their failure to comply with requirements for reducing animal suffering during their killing was rated as 'major'.

Farmers Fresh took over the abattoir in January this year. The company also has operations in Kenilworth, Warwickshire.

It sells slaughtered lambs to supermarkets in the UK and exports them to France.

Farmers Fresh Wales declined to comment when it was contacted by MailOnline.