California's laws on foie gras and the treatment of chickens could be undermined by federal legislation that would ban states from setting standards affecting farm products from outside the state.

The House Agriculture Committee this week approved an amendment to the farm bill that would prohibit states from imposing conditions on the sale of agricultural products that come from other states and comply with federal law.

The amendment was aimed at a state law written by Assemblyman Jared Huffman, D-San Rafael, that sets tougher rules on imported eggs sold in California starting in 2015. The law resulted from a 2008 voter-approved initiative that set strict rules on the treatment of egg-laying chickens in California.

However, the House amendment's broad language also could affect California's ban on the sale of foie gras and its higher standards for milk.

Petaluma egg farmer Arnie Riebli said Friday that California egg farmers won't be able to compete if Congress nullifies the state law. So doing would allow farmers in other states to sell eggs at lower prices in California than eggs from chickens kept in the larger cages.

If the amendment becomes law, Riebli said, "I'm dead. And all the egg producers are in California, too."

The agriculture committee approved the amendment in a marathon session for the once-every-five-years farm bill. The bill cleared the committee early Thursday morning.

Rep. Steve King, an Iowa Republican who represents the country's leading egg-producing state, said he introduced the amendment because the California law "scrambles and creates a patchwork quilt of state regulations."

California, he said, shouldn't be telling farmers in other states how to produce a product "that's already approved by the USDA or the FDA."

He also maintained the California requirement violates the Commerce Clause of the Constitution, which gives the federal government jurisdiction over interstate commerce issues.

Other members representing the South and Midwest expressed frustration with California's activism on agricultural and environmental issues.

"It is driving us crazy, because these things come to our states. And then they're trying to pass them in our states, and we don't want them," said Minnesota Democrat Collin Peterson, the ranking member on the committee.

But Rep. Dennis Cardoza, D-Atwater, opposed the amendment.

"California can't make your state do something," Cardoza responded to Peterson. But undermining California's law would hurt the state's economy, he said.

If "you can put small cages in Nevada, right across the border and our state can't prohibit it, then that's a problem for us," Cardoza said.

The amendment's passage was a swift turn of events for Riebli and other egg producers, who last year joined forces with their former adversary, the Humane Society of the United States. Together they supported an amendment to the farm bill that would have set national rules to increase the size of cages for laying hens.

Now Riebli and other state egg farmers who backed that effort find themselves fighting to stop a different amendment aimed at their livelihoods.

The King amendment also may allow farmers in other states to ship foie gras into California, according to the state Farm Bureau Federation. The state in 2004 passed a law to eventually ban the production and sale of foie gras. Eight years later, the ban took effect July 1.

The ban on production affected one California farm, a Sonoma-based business, Sonoma Foie Gras, one of two such companies in the U.S. At its peak it raised 25,000 ducks in San Joaquin County and had annual sales of about $5 million.

The owners of the 26-year-old company were unavailable for comment Friday.

The California Farm Bureau Federation has yet to take a position on the House amendment. But a spokeswoman said the language is broad enough that it might affect California dairy farmers and other agriculture sectors.

The state currently sets higher standards for drinking milk, as well for other products, said Rayne Pegg, manager of the federation's federal policy division.

For the past two days, Pegg said, her staff has been calling farm officials in other states and asking them, "Don't you have any other unique standards you'd like to keep?"

Les McCorvey, executive director of the Sonoma County Farm Bureau, said it's unlikely his organization would take a position on House legislation. But he maintained the current fight is an example of how farmers can get hurt by the "tangled web" of different rules caused by conflicting voter initiatives and state and federal laws.

"They would be put at a competitive disadvantage if this bill passes," McCorvey said.

The King amendment sparked outcries from animal rights advocates, and warnings that it could have far-reaching consequences beyond the treatment of birds.

"It is exactly the sort of thing that's done at midnight on a Wednesday night," said Scott Faber, vice president of government affairs at the Environmental Working Group. "We've never seen anything that would so profoundly threaten the ability of states to protect consumers, farmers and the environment."

Wayne Pacelle, president and CEO of the Humane Society of the United States, agreed the measure could nullify the foie gras ban and prevent states from enacting other needed laws.

"The scope of this amendment is so absurdly far-reaching that it's even difficult to talk about," Pacelle said.