Missouri is not going it alone in challenging the State of California’s egg law.

Attorney General Chris Koster has announced that five states have joined in his suit against California alleging that it is unconstitutionally trying to regulate farming practice outside its borders. Those states are Nebraska, Alabama, Oklahoma, Kentucky and Iowa.

With Missouri, those five states produce more than 20-billion eggs per year, 10-percent of which are sold to consumers in California.

California voters in 2008 passed Proposition 2 that, beginning next year, would regulate the size of the enclosures that house egg-laying hens. To avoid a potential competitive advantage to that state’s own egg producers, the California State Assembly passed a bill requiring producers in other states to comply with that law in order to sell eggs in California.

The six states’ suit asks the federal court to rule that California’s legislation violates the Commerce Clause of the United States Constitution. Koster says that clause prohibits any state from enacting legislation that regulates conduct wholly outside its borders, protects its own citizens from out-of-state competition, or places undue burdens on interstate commerce.

In a statement Koster says he welcomes those five states joining the effort.

“This case is not just about farming practices,” Koster says. “At stake is whether elected officials in one state may regulate the practices of another state’s citizens, who cannot vote them out of office.”