Briefing is now complete in a lawsuit filed by more than a dozen states asking the United States Supreme Court to block a California law requiring any eggs sold within the state to come from chickens that have sufficient space to stretch out in their cages.

In the lawsuit, filed directly with the high court in December, Missouri, Iowa and 11 other states allege that “California has single-handedly increased the costs of egg production nationwide by hundreds of millions of dollars each year” due to its stringent regulations prohibiting confinement of egg-laying hens. The complaint contends that California’s requirements violate the Constitution’s interstate commerce clause. The lawsuit also alleges that California’s regulations are preempted by the Egg Products Inspection Act (EPIA), a federal law requiring uniformity of labeling, standards, and other provisions allowing for free movement of eggs and egg products in interstate commerce. To support their claims, plaintiffs rely