The Humane Society of the United States released videos Wednesday that they say show animal-welfare violations at four egg farms in Iowa, the nation's top egg-producing state.

The videos, made secretly as part of the animal rights group's ongoing push to get egg-laying hens out of cramped cages, show chickens caught between wires and others being pulled dead from cages that sit above piles of manure.

"I think by any reasonable standard this is wholly unacceptable and insufficient to account for the physical and behavioral needs of any animal," said Wayne Pacelle, the Humane Society's president and chief executive officer.

Pacelle said industry standards allow for 67 square inches per bird with hundreds of thousands of birds per building. He said hens kept in the cages — known as battery cages — are trampled by other hens, suffer broken bones and can't reach food and water.

He also claimed hens are roughly handled and suffer from exposure to ammonia from the manure in pits below the cages.

"You cannot have good animal welfare by jamming six to eight animals in a small cage that doesn't allow them to turn around, extend their wings or engage in any natural behavior," Pacelle said. "And these facilities are so large and there are so many birds that when problems arise they're almost impossible to address."

Animal rights groups have used undercover video before to highlight practices at egg facilities, including last year when Chicago-based Mercy for Animals released video showing workers at West Des Moines-based Hy-Line North America tossing male chicks into a grinder. Industry groups say it's common practice because male chicks can't lay eggs or be raised quickly enough to be raised profitably for meat.

The latest videos were shot in February by an undercover employee at Rose Acre Farm facilities in Winterset and a Rembrandt Enterprises Inc. farm in Thompson.

K.Y. Hendrix, vice president for production for Rose Acres Farms, said his operation doesn't "condone anything anyone saw in the video."

"We have a document that everybody in the company signs that if you see any abuse ... report it to us so we can take care of it immediately," Hendrix said.

He said battery cages increase efficiency and production, reduce mortality and make for healthier birds.

"Fifty years ago we had cage-free chickens and over time we learned we could take care of them better if we put them in cages," he said.

Hens' cages are large enough to allow the animals to flap their wings and move around, Hendrix said.

"We monitor feed, we monitor water, we monitor temperature, they're in an environment that is good," Hendrix said.

A telephone message left Wednesday at Rembrandt was not immediately returned.

Pacelle said he is not accusing any worker, supervisor or manager of deliberate malice, but instead is trying to raise awareness about battery cage conditions. He said an increasing number of restaurants and stores are selling cage-free eggs, which often are produced alongside eggs from hens housed in battery cages to meet the growing demand.

Copyright 2010 The Associated Press.