According to AZCentral.com, the rules would mandate larger "enriched" cages where chickens could retreat to nests behind rubber privacy curtains, scratch on AstroTurf-like rugs and jump onto perches when they felt like it. Phased in over 15 years, the requirements would be costly to farmers who will have to expand barn space and replace equipment. But they are backing the measure.

"We want to do anything we can so consumers will say, 'Hickman's is doing the right thing, keeping us fed and doing right by their flock,' " said Clint Hickman, an owner of Arizona's only large egg farm. "And we want to stay in business."

For animal activists, "Our vision is birds having a decent life," said Wayne Pacelle, president of the Humane Society of the United States.

The compromise brought forward by egg producers and animal-rights activists would double the required cage size for laying hens nationwide and provide amenities that cater to natural bird instinct. The Egg Products Inspection Act Amendments of 2012 (HR 3798) before the House Committee on Agriculture gives farmers 15 years to replace the old-style battery cages - stacked wire containers that house hens in small compartments with slanted floors that allow eggs to roll onto conveyor belts. The "enhanced cages" must give each hen at least 124 square inches; the current average is 67 square inches.

It all started with an informal meeting last year in Scottsdale brokered by Jerry Crawford, an Iowa attorney, Democratic activist and part-time Arizona resident. Mr Pacelle was in town for a book signing; so was Chad Gregory, vice president of Georgia-based United Egg Producers. The two said Mr Crawford brought them together in his Scottsdale home for what turned into a five-hour discussion followed by months of tense negotiations. Mr Crawford declined to discuss his role or what prompted him to bring the two sides together.

"I was very skeptical that we would get to a positive outcome," Mr Pacelle said. "It was a long and difficult process that took months. Negotiations broke down five or six times."

The two sides had a years-long history of conflicts.

"With 285 million layers (laying hens) across the country, we estimated between $4 billion and $5 billion in additional expenses for new equipment and land," Mr Gregory said. "But egg producers wanted to survive, and the Humane Society through ballot initiatives was basically putting us out of business."

A 2008 Humane Society-backed ballot initiative in California requires all commercial egg production to be "cage free" by 2015. If similar initiatives followed, Gregory said many farmers would be forced out of business and eggs would be imported from overseas.

Now poultry farmers and animal activists are lobbying together for the same cause; Mr Gregory and Mr Pacelle made a joint appearance in Congress last week in support of HR 3798. Not all farmers are backing the plan. The American Farm Bureau Federation and beef and pork producers are opposing the cage mandate "because of the precedent it sets," said Jim Klinker of the Arizona Farm Bureau. "It is outlawing healthy and humane practices that have been developed in agriculture for decades. But we understand the business decision by the egg producers," he said.

The chicken-housing change, introduced by US Rep. Kurt Schrader, D-Oregon, has 52 co-sponsors, including Arizona Democrat US Rep. Raul Grijalva. It also has backing from United Egg Producers, the Humane Society of the United States, American Veterinary Medical Association, National Consumers League and dozens of local groups and producers.

Hickman's Family Farms near Buckeye and Kari Nienstedt, Arizona director for the Humane Society, are among them.

Clint Hickman said the effect on egg prices is uncertain. Carton labels must specify whether the eggs inside were laid in the old-style or "enriched" cages or in "cage free" or "free range" environments. But he is a vocal supporter and jokes about the two sides being "strange bedfellows."

Mr Pacelle said the Humane Society preferred cage-free mandates, but the compromise will give millions of chickens much better lives. It also would end his organization's state-by-state legislation push that could have benefited some of the birds but not all of them and could force concentration of poultry farms in states without strict regulations.

There are as many chickens in the United States as there are people, and humans consume 77 billion eggs a year, Pacelle said. The compromise on housing "is ... an example for other social-issue controversies where people set aside orthodoxy and elevate problem solving."