Ten years after passing a similar proposition, California is weighing in again on protections for animals, this time in a vote that could require all eggs to be cage-free by 2022. And yet, this time, animal rights advocates are split, offering dueling arguments that may be confusing for voters.

California's Proposition 12 would require factory farms to provide larger cages for hens, pigs, and calves, and penalize those who do not comply. On its face, the proposition seems to appeal unilaterally to animal rights groups: The measure's creator, the Humane Society of the United States, says it strengthens requirements that voters established in a previous proposition. Josh Balk, a vice president with the Humane Society, has called it "the most far reaching law for farm animals of all time."

Predictably, agriculture interests oppose the proposition, with the Association of California Egg Farmers and National Pork Producers Council arguing that new restrictions would raise prices for consumers and increase food shortages. Some animal rights groups have also joined the "no" vote, saying this measure undermines the progress made by a 2008 proposition.

The main difference between the two propositions is the standard being used to define confinement—and the consequence if farmers fail to meet it. The 2008 restrictions only require enough space for animals to "lie down, stand up, fully extend their limbs and turn around freely," which the Humane Society has said leaves loopholes for the egg industry. The new restrictions would specify cage measurements, making it harder for farmers to dodge the requirements, although People for the Protection of Animals argues that one square foot is still not large enough.

Factory farms, known to the industry as "confined animal feeding operations," produce 500 million tons of waste every year, according to the U.S. Environmental Protection Agency, contributing to air and water pollution across the country. Many operations have been criticized for animal rights abuses due to overcrowded cages. In California, hens have been at the center of this debate: Despite the 2008 proposition, one-third of the state's 15.5 million egg-laying hens are still confined in cages, the Mercury News reports.

Banning crates has been one way for voters to push for the regulation of these operations, which have historically taken advantage of loopholes in state law and often operate outside of federal purview. (For example, North Carolina's hog industry has sent millions of gallons of polluted waste into the state's waterways, despite attempts at state-level regulation.)

While legislation that restricts farming can be a tough sell in big agricultural states, appeals to animals' poor living conditions has had success with voters. Florida has led the way on animal cruelty ballot measures, according to the Animal Legal & Historical Center at Michigan State University. In 2002, the state passed an amendment prohibiting farmers from caging pigs during pregnancy. Other states followed suit: Alongside California, Arizona criminalized the confinement of pregnant pigs and calves.

Tuesday's results will show whether California voters will continue the trend or leave the debate at status quo. Californians have historically come down on the side of animals; the 2008 proposition passed with more than 60 percent of the vote.