The American Humane Association, which is overseeing animal welfare on the films, says no animals were harmed during the actual filming. But it also says the wranglers' complaints highlight shortcomings in its oversight system, which monitors film sets but not the facilities where the animals are housed and trained.

A spokesman for trilogy director Peter Jackson on Monday acknowledged that horses, goats, chickens and one sheep died at the farm near Wellington where about 150 animals were housed for the movies, but he said some of the deaths were from natural causes.

The spokesman, Matt Dravitzki, agreed that the deaths of two horses were avoidable, and said the production company moved quickly to improve conditions after they died.

"The Hobbit: An Unexpected Journey," the first movie in the planned $500 million trilogy, is scheduled to launch with a red-carpet premiere Nov. 28 in Wellington and will open at theaters in the U.S. and around the world in December.

The animal rights group People for the Ethical Treatment of Animals (PETA) says it's planning protests at the premieres in New Zealand, the U.S. and the U.K.

Kathy Guillermo, a senior vice president at PETA, said whistleblowers on The Hobbit contacted the organization after it had taken an active role in exposing problems on other movie sets. The organization sent a letter to Jackson last week outlining its concerns.

"We want to send a clear message to Hollywood that they need to be very careful when using animals and take all the precautions that need to be taken," Guillermo said.

The Associated Press spoke to four wranglers who said the farm near Wellington was unsuitable for horses because it was peppered with bluffs, sinkholes and broken-down fencing. They said they repeatedly raised concerns about the farm with their superiors and the production company, owned by Warner Bros., but it continued to be used. They say they want their story aired publicly now to prevent similar deaths in the future.

One wrangler said that over time he buried three horses, as well as about six goats, six sheep and a dozen chickens. The wranglers say two more horses suffered severe injuries but survived.

Wrangler Chris Langridge said he was hired as a horse trainer in November 2010, overseeing 50 or so horses, but immediately became concerned that the farm was full of "death traps." He said he tried to fill in some of the sinkholes, made by underground streams, and even brought in his own fences to keep the horses away from the most dangerous areas. Ultimately, he said, it was an impossible task.

He said horses run at speeds of up to 30 mph and need to be housed on flat land: "It's just a no-brainer."

The first horse to die, he said, was a miniature named Rainbow.

"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," Langridge said. "He was in a bad state."

Rainbow, who had been slated for use as a hobbit horse, was euthanized. A week later, a horse named Doofus got caught in some fencing and sliced open its leg. That horse survived, but Langridge said he'd had enough.

He and his wife, Lynn, who was also working as a wrangler, said they quit in February 2011. The following month, they wrote an email to Brigitte Yorke, the Hobbit trilogy's unit production manager, outlining their concerns.

Chris Langridge said he responded to Yorke's request for more information but never received a reply after that.

Wrangler Johnny Smythe said that soon after Langridge left, a horse named Claire was found dead, its head submerged in a stream after it fell over a bluff. After that, he said, the horses were put in stables, where a third horse died.

Smythe said no autopsy was performed on the horse, which was named Zeppelin. Veterinary records say the horse died of natural causes, from a burst blood vessel, but Smythe said the horse was bloated and its intestines were full of a yellow liquid; he believes it died of digestive problems caused by new feed.

Smythe said the six goats and six sheep he buried died after falling into sinkholes, contracting worms or getting new feed after the grass was eaten. He said the chickens were often left out of their enclosure and that a dozen were mauled to death by dogs on two separate occasions.

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

A fourth wrangler, who didn't want to be named because she feared it could jeopardize her future employment in the industry, said another horse, Molly, got caught in a fence and ripped her leg open, suffering permanent injuries.

Dravitzki, the spokesman for Peter Jackson, said the production company reacted swiftly after the first two horses died, spending hundreds of thousands of dollars upgrading housing and stable facilities in early 2011.

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

Dravitzki said Zeppelin died of a burst blood vessel and that he knew only of three goats, one sheep and about eight chickens that had died aside from that. He said two of the goats died in a cold snap but the third, like the sheep, was old and had likely died of natural causes. He said the chicken maulings were the result of careless staff oversight.

The American Humane Association said in its report on "An Unexpected Journey" that it investigated the farm at the production company's request. Dravitzki said the company contacted the AHA after Smythe alleged mistreatment of animals.

Mark Stubis, an association spokesman, said it investigated the farm in August 2011, months after the first deaths.

"We made safety recommendations to the animals' living areas. The production company followed our recommendations and upgraded fence and farm housing, among other things," the group said.

Dravitzki said the company had already made many of the recommended changes by the time the AHA made them.

Stubis said the association acknowledges that what happens off-set remains a blind spot in its oversight.

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

Dravitzki questioned the timing of the allegations with the premiere so close but said the producers are investigating all the claims "and are attempting to speak with all parties involved to establish the truth."

He said the company no longer leases the farm and has no animals left on the property. He said he didn't know if animals will be needed for future filming in the trilogy, but added that Jackson himself adopted three of the pigs used.

Hollywood has made animal welfare a stated priority for years.

In March, HBO canceled the horse racing series "Luck" after three thoroughbred horses died during production. The network said it canceled the show because it could not guarantee against future accidents.