Tom Silva's chickens pump out 1.4 million eggs a day, but his operation looks more like a prison than a farm.
To reach his hen houses, an intruder would have to scale 8-foot (2 1/2-meter) fences topped by razor wire, then sneak past surveillance cameras.
"Biosecurity" is the buzzword du jour at chicken, turkey and egg operations across the United States. A bird flu pandemic sweeping through flocks in Southeast Asia and beyond has spurred American commercial farmers to tighten their defenses.
"This is certainly the biggest issue facing the industry today, no question about that," said Richard Lobb, spokesman for the National Chicken Council.
The stakes are especially high in California, where a $2.5 billion (euro2 billion) poultry industry ranks among the top 10 producers nationwide for chicken, turkey and egg output. State officials say migratory bird routes that stretch southward from the Bering Strait and down the West Coast could bring the disease by this summer.
A tradition of raising "backyard chickens" for eggs, meat, cockfighting and bird shows runs deep in some Asian and Hispanic subcultures here in the Central Valley. Industry executives and state officials say these backyard birds number in the millions, and they worry these birds out in the open could be exposed to sick migrating flocks.
Then they could pass the disease to their owners - many of whom work at commercial poultry operations.
And there is painful precedent here. An outbreak of Exotic Newcastle disease killed more than 3.1 million birds, mostly poultry, in Southern California in 2002 and 2003.
Silva, vice president of the valley's J.S. West Milling Co., is as concerned about human carriers walking into his four facilities as he is about keeping sick birds out.
"If it gets into our industry, the only way to get it out is to euthanize complete complexes like this," he said during a tour of an egg-laying operation whose 1.5 million hens alone he valued at nearly $10 million (euro8 million).
The tour was brief, because no outsiders are allowed beyond the "STOP: BIOSECURE AREA" sign and razor wire - not even the lab workers who collect blood samples once a month for disease testing. They too are on Silva's payroll.
Even the short tour provided striking evidence of the measures the poultry industry is taking to combat bird flu before it reaches America.
Today, all trucks entering and exiting Silva's complex get an automated bath of ammonia-based disinfectant. Incoming drivers are asked where they've been and whether they've been exposed to poultry.
Every employee enters the site through a "dirty door" into a trailer that serves as a changing room. They swap their street clothes for pre-washed boots, hats and coveralls, then enter the hen houses through a "clean door." They reverse the process on the way out.
Various poultry companies even try to avoid each other on the road. They plot routes and stagger deliveries throughout the day, on the premise that the virus might jump from truck to truck.
The big rigs that rumble through the Central Valley most often bear the colorful logo of Foster Farms, which supplies dinner chickens primarily to consumers in the western states of California, Oregon and Washington.
Foster Farms is taking a different approach with its "broiler"-raising farms. One of its facilities, the 120-acre (48-hectare) Gurr Ranch, is not ringed by razor wire or even fencing. The hen houses are padlocked, and outsiders are not welcome, but the real emphasis is on making the ranch as repulsive as possible to migrating birds.
The resulting landscape looks like a moon base, intentionally devoid of trees and ponds but colonized by 64 identical outbuildings that house nearly 1.3 million chickens.
Migrating birds are looking for food, water and shelter, said Charles Corsiglia, an avian veterinarian on the staff of Livingston, California-based Foster Farms, the biggest poultry company in the West.