When California’s Proposition 2 took effect Jan. 1, it required that all veal calves, breeding pigs and laying hens in the state have enough space to “lie down, stand up, turn around, and freely extend their limbs” – hardly a radical animal rights manifesto.

Six years ago, California voters overwhelmingly endorsed the proposition, with nearly two-thirds backing the initiative. Since that time, the sentiment behind that proposition has reverberated around the nation and many major producers are converting to cage-free production systems.

It’s the smart business move. The American public is unlikely to accept cage-based systems, since egg production is basically the last bastion of extreme confinement in industrial agriculture.

The veal industry has almost entirely converted to crate-free systems, and earlier this month, the world’s top pork-producing company, Smithfield Foods, announced that it has converted more than 70 percent to crate-free production systems for its company-owned breeding sows. In fact, more than 60 major food companies – from McDonald’s to Costco – have agreed to stop buying pork from producers who confine their sows in gestation crates, which prevent the animals from even turning around for years on end.

These industries are on an inevitable course away from extreme confinement of animals. Major companies like Burger King, Marriott International and Nestlé have already pledged to switch to cage-free eggs nationally.

But some egg producers – stirred up by agribusiness lobbying groups whose leaders literally don’t want to give an inch for the animals – have refused to accept that consumers have spoken and that the future is cage-free. Along with their political allies, they’ve now sued four times to try to undermine California’s hen protection standards. So far they’ve lost each time.

It’s time for the holdout producers and retailers to recognize that cage confinement is not only inhumane and unsustainable but not popularly supported. Numerous studies also show higher levels of Salmonella contamination in caged hen factories than in cage-free facilities.

If we see a change in egg prices, it’s not far-fetched to conclude that egg sellers are taking advantage of the change in policy to secure some additional profits. Other factors that affect egg prices are far beyond California’s borders. For example, an avian influenza outbreak in Canada and Mexico is causing the U.S. to export eggs, which has added to demand and thus increased prices.

Prop. 2 gave egg producers six years to convert to more humane systems. If they chose not to use those years to prepare for the change, they may realize now that that was a bad business decision.

One day we’ll look back at this 50-year experiment of intensive confinement of animals on factory farms and wonder how good people could have allowed this kind of systematic mistreatment of animals to persist so long. But we’ll also be proud of those who saw a better way forward, pursued it and made it a reality.

Wayne Pacelle is the president and CEO of the Humane Society of the United States.