Amid a rolling landscape of browning chaparral and battered trailers, Alan and Ryan Armstrong’s metal hen houses line up like military barracks. Keeping their 450,000 birds safe – and Salmonella enteritidis out of their hen houses – is a daily battle.

Since they were old enough to drive the family skip loader and shovel chicken droppings, the Armstrong brothers followed a state-sanctioned quality-assurance program designed to curtail salmonella in eggs. So have dozens more California egg farmers, who helped develop the guidelines alongside federal and state officials following a salmonella outbreak 15 years ago that sickened thousands of people.

The program, which includes vaccinating hens and testing barns regularly for bacteria, has essentially wiped out salmonella on California farms, industry officials say. Yet only nine other states have enacted similar government-sponsored efforts.

One reason, the Armstrongs and other California farmers contend, is cost. Injecting chickens and swabbing cages takes money – not a fortune, but enough to send egg distributors searching for lower-cost sources.

“We have lost contracts over pennies a dozen,” Ryan Armstrong said. “They want cheap eggs.”

As the nation grapples with a salmonella outbreak that has made more than 1,500 people ill and led to the recall of 550 million Iowa eggs, the Food and Drug Administration has enacted rules that it said would prevent future outbreaks. The regulations force large operators to buy chicks and young birds, known as pullets, from firms that check for salmonella; create protocols to keep out pests; and perform salmonella tests in hen houses.