A leading Canadian animal rights group has released secretly-shot video footage of cruelty and abuse of chickens at two Alberta farms.

Canadian Press reports Mercy For Animals Canada recorded the undercover video footage at Creekside Grove Farms in Spruce Grove and Ku-Ku Farms near Edmonton. The video, which was aired on CTV's W5 program last week, shows hens cruelly crowded into battery cages, where they spend their entire lives, as well as chicks having their heads smashed before being thrown into garbage bags to suffocate to death, often while still conscious. The footage also shows dead hens rotting in cages and chicks covered in feces.

The battery cages shown in the video are considered so inhumane that they have been banned in the entire European Union, New Zealand and the US states of California and Michigan, Mercy For Animals Canada said.

"They're so crammed inside those cages they can't spread their wings, they can't walk, they can't engage in any of their natural behavior," Mercy For Animals Canada operations director Stephane Perrais told Canadian Press.

"They spend one year of their miserable life in there, basically producing eggs and after that time period, they're considered spent by the industry because their productivity has declined, and then they're slaughtered."

Mercy For Animals claims Creekside Grove Farms provides chicks to Ku-Ku Farms, which in turn supplies eggs to Ontario-based Burnbrae Farms, the main supplier of eggs to McDonald's Canada.

While McDonald's acknowledged that it does source eggs from Burnbrae Farms, it said it's eggs don't come from Ku-Ku and that the company gets "no eggs from the province of Alberta."

McDonald's released a statement denouncing animal cruelty.

"We care about the humane treatment of animals and believe they should be free from cruelty, abuse and neglect," the statement read. "Abuse is never tolerated in our supply chain and McDonald's has strict policies in place concerning the treatment of animals that our suppliers must adhere to at all times."

The animal rights group People for the Ethical Treatment of Animals (PETA) claims US and Canadian slaughterhouses supplying chickens to McDonald's kill the birds "using an outdated method that results in extreme suffering."

Peter Clark, chairman of Egg Farmers of Canada, an industry marketing and lobbying group, told CBC News that in more than 1,000 visits to egg farms, he's "never seen hens treated in the manner shown" in the video.

"I share the public's response to the video," Clark said. "The images were unacceptable."