Though state Department of Agriculture officials believe the virus has been confined to a 75-square-mile area, which has been under quarantine since May 16, poultry farmers across the state are taking extra precautions.
"We're definitely concerned about it. It's very contagious. We're not letting just anybody come into the chicken houses and egg plants," said Don Eby, vice president of the Shell Egg Division of Lehman's Egg Service in Greencastle, Pa.
Lehman's and most other poultry and egg producers in Franklin County are requiring all vehicles from Lancaster County - even those from outside the quarantined area - to be sanitized before entering their operations.
Wheelock Hatchery in Chambersburg, which hatches 5 million female chickens a year and ships them all over the East Coast, not only requires drivers to disinfect their trucks inside and out before and after each trip, but also to wear special coveralls, hats and boots.
"We're suiting up for the area. We're hoping it doesn't spread," said Victor Wheelock, president of the company.
Since the outbreak, poultry service companies and sales people - many of whom are based in Lancaster County - have been doing business over the telephone rather than making visits, Gayman said.
Feed and delivery truck drivers coming from Lancaster County pass through car washes to hose off their tires and undercarriages between trips, he said.
"It's an industry-wide courtesy thing," Gayman said. "Nobody wants to get blamed for carrying this."
Though the virus poses no threat to human health, it can be transmitted through humans, other animals, insects, machinery and vehicles.
The poultry farmers remember all too well the avian flu outbreak in 1983-84, which led to the destruction of 17 million birds in Pennsylvania, Maryland and New Jersey.
Though most Franklin County chickens were spared then, the area was quarantined and poultry operations weren't allowed to ship their products outside the I-81 buffer zone, Wheelock said.
At this point, the virus detected in Lancaster County is non-pathogenic, meaning it has not developed into a virulent or destructive strain, Hoffman said.
But to prevent the virus from mutating into a deadly strain and spreading, the affected flocks, numbering about 830,000 birds, have been destroyed and buried.
No live poultry or poultry products can move in and out of the quarantined area without a permit , said Sally Bair, spokeswoman for the state Department of Agriculture.
Pennsylvania State Police are working to enforce the quarantine, Bair added.
Officials say the virus may have been carried out of New York City by a live bird market dealer and hauler.