Hundreds of neglected and emaciated dogs have been rescued from a rural property in Alberta, in what the province's SPCA is calling the largest case of dog neglect in its history.

The dogs were removed from a farm east of Milk River near the U.S. border earlier this month. According to court documents, most were chained to posts in and around abandoned vehicles and farm machinery, and some had no protection from the winter cold.

The animals' owner, April Irving, voluntarily surrendered 60 dogs in December, following a complaint from a neighbour.

Another 141 were seized by the SPCA two weeks ago, with the help of peace officers who arrived with a search warrant. Five dead puppies were also removed from the property.

A dozen animal rescue groups throughout Alberta are now caring for the dogs, including the Alberta Animal Rescue Crew Society (AARCS), based in Calgary.

AARCS Executive Director Deanna Thompson says even seasoned rescue workers are shocked at the condition of some of the dogs.

"The animals are in horrible condition," she told CTV Lethbridge, noting that most of the dogs were emaciated, had skin conditions and badly matted fur.

"We've seen a lot of injuries," Thompson said. "We have a dog with a broken leg, a puppy with a broken jaw, another dog that's missing a leg."

Thompson says her group sees a lot of cases of abuse and neglect, but this is by far the worst in its history.

The dogs’ owner is well known to animal rescue officials. Court documents show the SPCA had to seize dogs from Irving in 2007, when she was living in Fort McMurray. Then in 2010, the Saskatchewan SPCA had to remove 82 dogs from her property near Foam Lake.

Several breeds of dogs were seized in this incident, including Huskies, Irish wolf hounds and Malamutes. In previous seizures, Irving has characterized herself as a dog breeder. But Roland Lines of the Alberta SPCA says his group is not even sure why the owner had so many dogs.

"There's no evidence of any kind of organized breeding facility. The individual didn't seem to be rescuing dogs in any sense. (She) seems to have just collected a large number of dogs and then allowed them to interbreed," he said.

Irving filed a statement of claim against the SPCA, seeking to have all the dogs and items of her property returned. She says all she wants to do is live in peace with her animals.

That appeal has been denied and ownership of the animals has been transferred to AARCS.

The rescue group says many of the dogs will need extensive vet care and long-term treatment before they are healthy enough to be put up for adoption.

So far, no charges have been laid. The SPCA says the investigation continues.

With a report from CTV Lethbridge's Terry Vogt