Missouri's attorney general is asking a federal judge to strike down a California law regulating the living conditions of chickens.
The lawsuit takes aim at a California law barring the sale of eggs produced by hens kept in cages that don't meet California's size and space requirements.
The California egg law is to take effect in 2015.
Missouri Attorney General Chris Koster contends the California law violates the interstate commerce clause of the U.S. Constitution by effectively imposing new requirements on out-of-state farmers.
Koster says Missouri farmers sell about 540 million eggs annually in California and would have to spend about $120 million to remodel their chicken cages if they want to remain competitive.