Gov. Terry Branstad has joined other governors of egg-producing states to protest a California law that gives chickens the ability to cluck and pluck and spread their wings without touching another bird, if they are so inclined.

In 2008, California voters approved a ballot referendum requiring "colony cages" for laying hens. Lawmakers, worried that the law would place California producers at a competitive disadvantage, amended the law to require that all eggs sold in the state come from chickens raised in the large enclosures. The California law requires about 116 square inches of space per bird. The industry standard is 67 square inches.

Iowa is the nation's No. 1 egg-producing state, generating about 15 billion eggs a year, with 30 percent of those shipped to California, the top importer of Iowa eggs.

Branstad said today in a release that he is joining the governors of Missouri, Nebraska, Oklahoma, Alabama and Kentucky in a federal lawsuit that claims the California law is an unconstitutional restriction on interstate commerce and protects its citizens from outside competition.

"California's effort to unconstitutionally limit the ability of Iowa farmers to access California's consumers must be stopped. I support all efforts to uphold the right of Iowa farmers to sell their products, including eggs, in every state free from unconstitutional restraints imposed by any state," Iowa Secretary of Agriculture Bill Northey said in a release.

Colony-cage laws also have been approved in Michigan, Oregon and Washington State.