GUANAJUATO, Mexico – Mexico slaughtered more than a million chickens infected with bird flu in an effort to prevent the virus's spread, according to news reports. The H7N3 virus was detected at 18 farms in the central state of Guanajuato.

CNN reported that authorities gave different tallies of how many birds were killed. On Feb. 25, Agriculture Minister Enrique Martinez said more than 2.1 million chickens were slaughtered, including 519,000 egg-laying hens, 722,265 breeder chickens and 900,000 chickens raised for food. Javier Usabiaga Arroyo, a state agriculture official, said the total was 1.2 million, according to CNN, citing a report from Mexico's state-run Notimex news agency.

Pilgrim's Pride, Greeley, Colo., and Industrias Bachoco both have poultry operations in the effected region. Pilgrim's said the complex has been isolated and the company received permission to vaccinate breeders and grandparent stock in unaffected areas. Bachoco also started a vaccination program at its facilities.
At least 1.9 million chickens have been vaccinated since the outbreak began, and officials plan to vaccinate millions more. The Agriculture Ministry stressed that the virus poses no threat to humans.