An animal rights group claims to have obtained undercover footage from the inside of a free range chicken farm showing cramped conditions, overcrowding and sick, neglected poultry.

The RSPCA-approved coops, in the north of Perth, are home to chickens producing eggs which are sold at Woolworths, IGA and Coles with a guarantee the animals are treated well and are allowed to roam free.

But animal rights videos claim to have exposed Mt Barker Free Range Farms mistreating the chickens, leaving dead birds to rot while others appear to suffer from burns and respiratory problems, Seven News reports.

Scroll down for video

Footage from inside the free range chicken farm appeared to show the birds living in cramped, overcrowded coops. Mt Barker Free Range Farms says the footage was taken at night when the chickens are brought inside for protection

Activists filmed birds that looked to have burns (pictured) and allege some suffered from respiratory problems. Mt Barker Free Range Farms says the images show birds with healthy pink skin who have not feathered or have lost feathers as part of free ranging

Animal activists filmed what they described as distressing scenes of thousands of chickens kept inside overcrowded cages as they pecked at the rotting corpses of other birds, while others appeared unable to stand or walk properly.

Nadia Schilling, from In Defense of Animals, told Seven News customers pay premium to ensure they are eating eggs that were cultivated in a safe, humane environment.

'Consumers need to be guaranteed... that they're being checked in on every day, they're not suffering from thirst, hunger, neglect, deformities,' she said.

Animal rights groups have campaigned for free range chicken farms to install live-streaming cameras to prove to consumers the birds are treated well and live in a stress-free environment.

But Mt Barker Free Range Farms has firmly denied any of its chickens are harmed, and says the 'staged' footage was filmed at night when the birds are brought inside.

'The opening shots of the video show happy, chirping birds. We have two documented external, independent, professional audits within weeks of the date of these allegations showing no such suffering and good conditions in the housing,' a statement reads.

'Our staff walk the chicken houses and the free range area twice a day looking for any birds that have died or might be in trouble. Sometimes a death or injury occurs after they have left.'

Animal activists filmed scenes of thousands of chickens kept inside cages as they pecked at the rotting corpses of other birds, while others appeared unable to stand or walk properly. But Mt Barker Free Range Farms has denied any mistreatment or neglect of the animals

Animal rights groups have campaigned for free range chicken farms to install live-streaming cameras to prove to consumers the birds are treated well and live in a stress-free environment

It says the farm has been recently audited and cleared by the RSPCA and that it treats its chickens 'extremely well'.

'Our view is that the video has been staged. We rely on RSPCA auditing and no non-conformance was identified,' a spokesperson told Daily Mail Australia.

'After dealing with the chickens for three weeks the activists only found three dead birds, which is actually a very low mortality rate.'

It also says the 'ammonia burns' are just the chickens' pink exposed skin and that the birds are 'happy and healthy'. It says ammonia burns are identifiable by burns on the footpads and caused by wet litter (floor bed) conditions.

After being questioned about chickens pecking at other carcasses, Mt Barker said: 'Chickens are omnivores they eat insects and peck at each other hence the term 'pecking order' it is an instinct. We endeavour to avoid birds pecking each other but, we do not clip their beaks and sometimes animals turn on each other.'

Mt Barker's website reads: 'It sets itself the highest possible standards of free range to ensure our chickens live in a happy and stress-free environment. Our stress free growing conditions give free range animals their superior taste and texture.'

Daily Mail Australia has contacted the RSPCA for comment.