SAN DIEGO -- Battery-sized cages crammed full with laying hens are images driving a campaign to change the way eggs are produced for market.

"Most hens can't even spread their wings," said Paul Shapiro of the Humane Society of the U.S.

Shapiro is demanding more humane conditions for laying hens in the United States.

"This confinement is cruel and inhumane and should be banned," said Shapiro.

Protesters are taking on big retailers to stop selling so-called battery-cage eggs.

The most high profile demonstrations in the last year zeroed in on Trader Joes, pressuring the popular chain to follow the lead of competitor Whole Foods.

"You're going to have a better product and customers would be hard-pressed not to appreciate that," said Justin Jackson of Whole Foods.

In San Diego, the Animal Protection and Rescue League is also trying to educate consumers.

"If people have to eat animal products, we ask them to so some homework to make sure the animals are raised in the least cruel way possible," said animal advocate Bryan Pease.

As a result of these efforts, big grocers and specialty markets now offer consumers more choices at the egg case.

Every carton of eggs has a "sell by" date and code numbers that tell where the eggs are from, 10News reported.

The USDA has a poultry Web site. Just type in the code numbers and you'll find the farm with addresses and phone numbers so you can contact them with questions or concerns.

10News went to the biggest egg ranch in San Diego County. There are 1 million hens, and they are inspected every month by a vet to make sure they are healthy.

Mark Brand is a poultry veterinarian and said he finds it difficult to mask his frustration with protesters.

He said it's impractical and could be unhealthy for chickens and consumers to release the nation's 228 million egg-laying hens.

"In Europe they've gone cage-free. They're putting hens on the ground, and they're now seeing diseases they haven't seen in 30 to 40 years that they can't cure or treat," said Brand.

But cage-free is an idea that could fly with consumers.

"I hate to see things suffer. (I would) love to see something better for chickens," said a consumer.

"Now that I know what's going on, I definitely prefer free range," said another consumer.

For more information, click on Humane Society of United States Web site www.hsus.org and the Animal Protection and Rescue League Web site www.APRL.org.