UPDATE, MARCH 9: A flock of chickens at a commercial poultry breeding operation in Giles County in southern Middle Tennessee has tested positive for low pathogenic avian influenza (LPAI), according to the Tennessee Department of Agriculture. 

Officials don't believe think the infection is related to a facility in neighboring Lincoln County that tested positive for a strain of highly pathogenic avian influenza earlier this month.

The two facilities are operated by different companies, the agriculture department said. 

Neither HPAI or LPAI are a risk to the food supply, and none of the affected chickens have entered the food chain, the agriculture department said.

The avian flu was detected at the Giles County facility during routine screening tests on March 6. 

"This is why we test and monitor for avian influenza," State Veterinarian Dr. Charles Hatcher said in a statement. "When routine testing showed a problem at this facility, the operators immediately took action and notified our lab. That fast response is critical to stopping the spread of this virus." 

Officials said the affected chickens have been put down and buried. They did not say how many chickens were destroyed. 

The facility is under quarantine, and domesticated poultry within a roughly 6-mile radius of the site are under quarantine and are being tested for illness. No other flocks have tested positive for the virus or shown signs of illness as of Thursday. 

Agriculture officials ask commercial and backyard poultry owners to closely observe their chickens and report any sudden increases in the number of sick or dead bird deaths to the state veterinarian's office.

PREVIOUS STORY, MARCH 8: State agriculture officials say no additional cases of avian flu have been found within a 10-mile radius of a Lincoln County facility were it was detected earlier this month.  

The Tennessee Department of Agriculture was alerted to the presence of a strain of highly pathogenic avian influenza (HPAI), informally known as bird flu, at the southern Middle Tennessee facility on March 3. 

Agriculture officials put down more than 73,000 chickens at the facility, which is a supplier for Tyson Foods. 

The agriculture department said Monday it still investigating the source of the virus, but no additional poultry within the 10-mile surveillance area have shown signs of illness, and all samples from poultry within the surveillance area have tested negative for HPAI. 

USDA's National Veterinary Services Laboratories has confirmed the virus affecting the Lincoln County facility is H7N9. This is not the same virus as the China H7N9 virus affecting Asia, the department said.

MORE: Experts: Avian flu detected at Tennessee plant won't affect food supply

HPAI does not pose a risk to the food supply. The agriculture department said none of the affected animals have entered the food chain and the risk of human infection is very low. 

"This is highly pathogenic for birds, it's not for us one bit. This is not for humans at all," said Dr. Lou Strickland, a veterinarian with the University of Tennessee Extension. “You’d have to physically have contact with the sick animal to actually have any transfer of disease."

Officials said they will continue monitoring commercial and backyard poultry for signs of influenza, and all flocks in the surveillance area will be tested again.