Stacked rows of metal cages, each crammed with eight hens, extend longer than a football field in the chicken sheds at Westminster's County Fair Farms. The birds peck at one another. They live suspended above pits of their own waste, shut off from sunlight and fresh air.

The conditions, which allow a half-million hens to produce millions of eggs a year, meet all legal and industry standards, say those who run the farm. But their henhouse was recently the site of a covert operation in which a group of animal activists known as Compassion Over Killing shot video and still pictures and abducted several birds for delivery to a veterinarian.

"It was a horrible place," said Paul Shapiro, the group's spokesman and a proud vegan (a strict form of vegetarian diet) who believes that if people knew the truth about most egg farms they'd never eat an omelet. "And the worst thing is, it's typical."

Compassion Over Killing is a small organization, with only two full-time employees, and its cause might strike some as frivolous. But the issue of chickens' rights has drawn attention from a growing number of corporate giants - including McDonald's, which has required that the egg farms it buys from give hens more space.

"Those are just the first steps, but certainly, it's a relief to see companies taking notice," Shapiro said.

The conditions on egg and poultry farms first drew the attention of animal-rights activists in the late 1980s, as they shifted their focus from endangered species to farm animals. Activists accused the poultry industry of genetically engineering chickens raised for meat, called broilers, to carry more flesh than their skeletons can comfortably support. Then, national groups such as People for the Ethical Treatment of Animals, or PETA, began protesting the use of battery cages, the term for the long rows of metal cages at most egg farms.

Responding to these protests, the European Union announced it will require more spacious cages after 2012, and corporations such as McDonald's have decreed that they won't buy eggs from companies that induce greater production through starvation, a process called forced molting.

Compassion Over Killing, founded in 1995 and based in Takoma Park, did not take up the chickens' cause until last year, when the group sneaked into a farm in Cecil County and shot footage that was later compiled for a video titled Hope for the Hopeless.

Looking for another farm to infiltrate, Shapiro and his cohorts picked County Fair based on an anonymous tip suggesting they might find hens in poor condition. County Fair lies north of Westminster, where the city gives way to farmland.

Shapiro, 23, said the mission was not carefully planned.

"We just showed up and walked in, basically," he said.

The video shot during visits over several nights last spring shows young adults wearing gray sweat shirts with "Compassion Over Killing" printed across the chest in bold black letters.

Hens in the videotape and pictures purportedly shot during the raid appear gaunt and sluggish, their scant feathers are yellowish-brown and their bodies covered with scars and infections. Live birds appear to be caged with dead ones, and several birds appear to have died after entangling themselves in cages. During their last incursion, the activists seized 10 birds from their cages and took them to a veterinarian for treatment.

Farm supervisors at County Fair said the birds might not have a lot of space (about 53 square inches per bird), and they said the hens pluck one another's feathers. But, said Chris Pierce, a consultant who works with the farm, the birds' diets are carefully managed, and their cages are ventilated. He also said that workers regularly walk the aisles to remove dying birds and untangle those who have become stuck in cages.

"When a bird is stressed, she doesn't perform as well, so we want them to be as comfortable as possible," Pierce said.

Shapiro says his attempts at lobbying Maryland legislators to expand animal cruelty laws to livestock haven't succeeded. But he hopes that by documenting conditions at egg farms he will inspire voters to demand action from their elected officials.

He said he's not interested in singling out Maryland - which produces about 845 million eggs a year, a figure dwarfed by industry leaders such as Indiana, which produces about 6 billion eggs a year - and he's not trying to single out County Fair Farms.

He said he wants people to know that such conditions are the rule at egg farms in every state. The mortality rate at County Fair, which loses about 500 birds in a bad week, might be in line with industry standards, said Shapiro, but industry standards are inadequate.

When allowed to forage and roam freely, the type of hens used at most egg farms have fluffy white feathers and proud red combs and can live as long as 10 years, Shapiro said. Farm hens rarely look so vibrant and live about two years on average, animal rights activists say.

"We're willing to sacrifice for these birds," Shapiro said. "What's happening to them is just so obviously wrong."

Shapiro's views are shared by other animal-rights supporters.

Karen Davis of United Poultry Concerns said most Americans are so removed from the world of modern farms that they have no idea what's going on.

"They don't know that poultry, like people, can experience terror and pain, a really wide variety of suffering," Davis said. "It's impossible to exaggerate how horrible these birds' lives are from beginning to end."

Pierce, the consultant for County Fair Farms, declined to comment on the activists' clandestine tapings or their hen heist. However, he said he expects that a new set of standards released by the Food Marketing Institute, a group of retailers including the supermarket chains Safeway and Kroger, will push farms such as County Fair closer to practices favored by animal-rights activists.

The standards, which hundreds of large egg buyers are expected to follow, will require gradual increases in cage space with an eventual goal of 67 square inches per bird in six years. The standards will also demand that farms look for alternatives to forced molting.

"People just need to understand that there are two sides to this issue," Pierce said. "We're willing to work on the conditions, but we also have people to feed."

The interest of major customers such as the fast-food chains has forced farmers to confront the animal-rights issues involved in egg production, said Paul Zimmerman, poultry scientist at the University of Maryland. He said that if enough people refuse to buy eggs of chickens kept in battery cages, then battery cages will disappear.

"The customers will determine the moral center on this issue," he said.