STRATHROY, Ont. - At the "dog gulag of Middlesex County," dead animals were tossed in pits with other refuse, their remains left to rot or be pecked at by chickens.

The sight one is one of many horrors found Thursday by investigators in what they say is the largest-scale case of animal neglect they've seen.

About 120 dogs were found in terrible conditions, some in need of medical care, at a rural property near Strathroy in southwestern Ontario.

The scene left Sarnia, Ont., police Const. Beth Lahey fighting back tears.

It was the first visit there for Lahey, who described the operation -- licensed as a kennel -- as the "dog gulag of Middlesex County."

"Animals are subsisting in absolute squalor, filth. There's carcasses in various states of decay, consumption,'' she said.

Investigators for the London Humane Society have been frequent visitors to the site, most recently in January.

"We have been trying to work at increasing the standard of care out there for a number of years," investigator Chris Chew said as he tried to take inventory of the dogs.

The dogs' owners promised to make improvements but didn't follow through, he said.

"Some of the concern (now) is that things should have been done," Chew said.

Chew and colleague Leanne Mackay were called to the site Wednesday by police in Sarnia searching for stolen property.

While police found enough suspect property to fill one-third of a police cube van, they were stunned to find the nightmarish conditions in the kennels.

Dogs of all types and sizes, were kept in pairs in kennels exposed to the elements on one side and so filled with mud and excrement the animals couldn't turn around without stepping in feces.

"This is by far the biggest operation I've ever seen," said Mackay, who has worked a decade as an investigator for the London Humane Society.

A dozen dogs ran loose, some seemingly vicious and injured or ill, while others were chained to kennels.

Other animals ran loose too, including sheep, goats, pigs, chickens, duck, geese, some of them in poor health.

"It was absolutely horrible. Animals were eating garbage, eating the carcasses of other animals,'' Doug Graham, a provincial police spokesman, said Thursday.

Police believe the owners were breeding dogs but weren't sure for what purpose -- dog fighting and other activities hadn't been ruled out, Graham said.

Floriano Daponte, 53, of Napier, Ont., is charged with possession of stolen property.