Peter Jackson
Peta plans to hold protests at the premieres of The Hobbit: An Unexpected Journey after at least 27 animals died at an unsafe farm during filming (Reuters)

Up to 27 animals were killed during the filming of Peter Jackson's new trilogy The Hobbit because they were kept in an unsafe farm, activists have claimed.

The American Humane Association, which oversaw animal welfare during filming, said that although no animals were harmed during the actual shooting of the film, there were complaints about where the animals were housed and trained.

Four wranglers said the farm where the animals were kept was unsuitable for horses because it was covered in bluffs, sinkholes and broken fencing.

They had repeatedly raised concerns about the safety of the farm with production executives at Warner Bros but their fears were ignored.

One wrangler said he buried three horses, six goats, six sheep and a dozen chickens. Two more horses were severely injured although they survived.

Matt Dravitzki, a spokesman for Jackson, said that horses, goats, chickens and one sheep died at the farm near Wellington, New Zealand.

He confirmed 150 animals were housed for the films and said some deaths were a result of natural causes.

Two horse fatalities, however, were avoidable but at least led to improvements in conditions in the stables.

"We do know those deaths were avoidable and we took steps to make sure it didn't happen again," he said.

Chris Langridgie was hired as a horse trainer in 2010 and was responsible for overseeing 50 horses. He said he became concerned about the "death traps" on the farm, particularly sinkholes that had been created by underground streams.

He tried to fill in some of the holes and erected fencing out of his own pocket to keep horses away from dangerous areas. His attempts, however, proved futile, he said.

The first horse to die was called Rainbow. Langridgie said: "When I arrived at work in the morning, the pony was still alive but his back was broken. He'd come off a bank at speed and crash-landed. He was in a bad state."

A horse called Doofus got caught in some fencing and cut its leg open although this horse survived.

Johnny Smythe, another wrangler, said a horse called Claire was found dead shortly after Langridgie left in February 2011. She drowned in a stream after having fallen over a bluff.

Smythe was fired in October 2011 after arguing with his boss over the treatment of the animals.

The American Humane Association said it investigated the Wellington farm at the request of the production company. Mark Stubis, a spokesman for the association, said: "We made safety recommendations to the animals' living areas. The production company followed our recommendations and upgraded fence and farm housing, among other things.

"We would love to be able to monitor the training of animals and the housing of animals. It's something we are looking into. We want to make sure the animals are treated well all the time."

The Hobbit: An Unexpected Journey, is the first of the $500m trilogy based on The Hobbit by JR Tolkien. It is due to be released in the UK on 13 December.

Animal rights group People for the Ethical Treatment of Animals will hold protests at the premieres in New Zealand, the US and the UK.