The U.S. Supreme Court has taken a pass on a pair of poultry-related California laws -- one requiring minimum cage sizes for hens laying eggs sold in California and the other banning production and sale of foie gras, a wire service is reporting.

Fifteen states are suing to overturn provisions related to Proposition 2, the cage-free law passed by California voters in 2008, and a similar Massachusetts law on the grounds that they violate the interstate commerce clause of the U.S. Constitution.

The U.S. Supreme Court did not cite a reason for rejecting the lawsuits Monday, although its order stated that Justice Clarence Thomas would have taken up the cases, The Associated Press reports.

The U.S. Justice Department had urged the high court not to step in to resolve the issue, arguing that interstate commerce disputes are best resolved by district courts, according to the AP. The attorney general's office in Missouri, which led one of the lawsuits, told the wire service on Tuesday it plans to keep fighting for local farmers and consumers.

The Humane Society of the United States-backed Proposition 2 required caged hens to be given enough space to move freely and extend their limbs. At the request of farmers who felt the law put them at a competitive disadvantage, the Legislature later passed a law requiring all eggs sold in California to be produced under those rules, prompting the interstate commerce challenge.

The Association of California Egg Farmers notes on its website that its members supported the agreement between the industry, retailers and the HSUS that would have phased in 100 percent cage-free egg production by 2025. But the group opposed Proposition 12, which passed in November and requires all eggs sold in the state to be cage-free by 2022.

The legal maneuvers come as scientists from the University of California-Davis, Iowa State University and the USDA's Agricultural Research Service concluded recently that cage-free hens are more expensive to feed and have double the mortality rate of those in conventional cages. Further, the report appeared to dispute animal welfare advocates' assertion that hens in conventional cages are stressed.

Meanwhile, lawsuits have been making their way through the courts since the Legislature in 2004 banned foie gras, a fatty goose or duck liver made by force-feeding the birds. The French-born dish is considered a delicacy in high-end restaurants, although most such restaurants in California had stopped serving it by the time the law took effect in 2012.