As of Jan. 1, 2012, egg-laying hens across many European countries will live with fewer discomforts: The European Commission has officially implemented its ban on battery cages, the notoriously cramped cages used by many egg farmers and criticized by animal rights proponents and veterinarians who call them cruel and harmful to the birds’ welfare.

The law, finalized in 1999, comes after a 12-year “phase-out” period meant to allow egg farmers time to implement the costly transition away from battery cages. According to the Scotsman newspaper, replacing battery cages with more-hospitable “enriched” cages has alone cost U.K. egg producers an estimated £400 million ($613 million).

Most farmers in participating countries have opted for the enriched cages, installing roomier enclosures that allow hens to stretch their wings, roost on an elevated platform and nest in a designated nesting area. Others have arranged for barns or other free-range systems, but the law now clearly reserves hens a seat at a nest.

That opportunity to properly nest will do the most to improve hen well-being, said Ian J.H. Duncan, Ph.D., Emeritus Chair in Animal Welfare at the University of Guelph in Ontario and the President of the Animal Welfare Foundation of Canada. Duncan has been studying the effects of battery cages on hens since the early 1970s, when he worked at the Poultry Research Centre in Edinburgh, Scotland.

“I wasn’t sure if I was going to live to see this, to be honest,” Duncan told Food Safety News. Since he began his career, he has been a vocal critic of battery cages, the use of which has progressively worsened over the decades, he said.

Battery cages first gained favor among farmers by introducing a new standard of hygiene and reducing the spread of infectious diseases among flocks. The cages were bigger at first, too, and housed one bird per cage. Today, a single cage will typically house multiple birds, leaving little to no room for walking or stretching. 

“The biggest problem is they prevent the bird from doing a lot of its natural behavior, but particularly bad is the prevention of nesting behavior,” Duncan said. “About an hour before laying an egg, a hen will separate from the flock to look for a nesting place. If it can’t find one, it starts to feel agonized and distressed.”

But for some European farmers, the distress has shifted from the hens to them. Since the ban went into effect three weeks ago, some countries have done much more to enforce the new law than others, creating a price discrepancy between locally produced eggs and cheaper imports from countries that aren’t following the rules.

According to the Scotsman, the European Commission has announced plans to take legal action against the 13 countries not enforcing the rule: Hungary, Italy, Latvia, Spain, Greece, Belgium, Bulgaria, Cyprus, Poland, Portugal, Romania, Slovakia and the Netherlands. In the meantime, some stores in the U.K. have pledged not to carry any eggs from battery cage facilities, which may still produce an estimated 51 million eggs per day–one-quarter of Europe’s total production.

Some worry that the same inconsistencies among countries will arise this time next year when a similar rule will outlaw the use of gestation crates for pigs after the first four weeks of pregnancy.

Leading the movement away from battery cages, Germany banned the practice in 2007. Duncan said there was little to indicate a similar transition would happen in North America, where the vast majority of eggs are produced by hens in battery cages.

But some big-name companies are taking small steps away from battery cages. According to the Humane Society of the United States, International House of Pancakes (IHOP) has agreed to begin testing cage-free eggs in its restaurants after coming under scrutiny for using only battery-cage egg suppliers.

Duncan also used to serve on Burger King’s animal welfare advisory committee. In 2007, Burger King announced that it would slowly transition toward eggs and pork that did not come from caged animals.

The fast food giant started small, buying two percent of its eggs from cage-free suppliers and vowing to switch over by increments of at least two percent each year.

“Now, they’re at 10 percent,” Duncan said. “It’s a start.”