The Humane Society of the United States and the United Egg Producers — bitter rivals on animal welfare issues — Thursday took the food and agriculture community by surprise. The two groups joined forces to announce a new, unprecedented agreement to push for federal legislation to mandate animal welfare standards on egg farms. If such a bill clears Congress, it would be the first to mandate the treatment of livestock on the farm — current humane handling standards apply only to slaughter practices.

With the landmark agreement, the groups will end the fight over two contentious ballot initiatives in Washington and Oregon state that would have contributed to what is becoming a piecemeal system of standards. The egg industry has pledged to make an estimated $4 billion investment to overhaul industry practices over the next 15 years.

The proposed overhaul includes phasing out all conventional battery cages and phasing in enriched housing systems, including perches, nesting boxes, and scratching areas that provide laying hens almost double the amount of space. Feed and water-witholding molting, a practice already being phased out, would be prohibited as would excessive ammonia levels in hen houses. Eggs that don’t meet the new standards would not be allowed for sale in the U.S. under the new proposal.

“We are really excited, as an industry, about it,” said Bob Krouse, a fifth generation Indiana egg farmer and chairman of the United Egg Producers, the industry group representing the vast majority of the U.S. egg industry, which currently utilizes 280 million hens, 90 percent of which are in battery cages. Those hens produce about 6 billion eggs per month.

Leaders on both sides praised the cooperation.

Krouse pointed out that the industry preferred a unified federal law over state ballot initiative uncertainties and emphasized the unprecedented nature of the deal.

“We are committed to working together for the good of the hens in our care and believe a national standard is far superior than a patchwork of state laws and regulations that would be cumbersome for our customers and confusing to consumers.”

“This is the first agreement like this in the country,” noted Krouse.

That fact has other livestock groups concerned. HSUS remains enemy number one for many in animal agriculture. The group is often chided for its undercover videos and sometimes controversial tactics.

The pork industry criticized the move.

“NPPC is gravely concerned that such a one-size-fits-all approach will take away producers’ freedom to operate in a way that’s best for their animals, make it difficult to respond to consumer demands, raise retail meat prices and take away consumer choice, devastate niche producers and, at a time of constrained budgets for agriculture, redirect valuable resources from enhancing food safety and maintaining the competitiveness of U.S. agriculture to regulating on-farm production practices for reasons other than public health and welfare,” said the National Pork Producers Council in a statement Thursday.

Though the agreement doesn’t move all egg production toward cage-free, as HSUS would like, the group said that millions of animals would benefit from the industry-wide makeover.

“Passing this bill would be an historic improvement for hundreds of millions of animals per year,” said Wayne Pacelle, president and CEO of HSUS.

Egg industry representatives said they would be closely monitoring and studying the humane standards’ impact on food safety.

“We have to make sure that we’re not giving up anything on the food safety front,” said Krouse, who said the industry would still be following the new U.S. Food and Drug Administration guidelines.