The bird flu has struck another Rembrandt Enterprises farm, marking the state's single largest outbreak of the deadly virus. Two million egg-laying chickens will be destroyed over the next four weeks at the company's Renville operation, officials said Saturday.

One barn holding around 200,000 birds was infected, but the entire flock will be killed as a precaution.

Chickens at the farm have tested "presumptive positive" for the disease "despite the herculean efforts of Rembrandt's employees to keep our facilities virus-fee," said Jonathan Spurway, the company's vice president of marketing.

Rembrandt Enterprises, one of the nation's largest egg producers, suffered an outbreak in its Rembrandt, Iowa, facility May 1, contaminating one barn housing about 250,000 hens. Its third plant, in Thompson, Iowa, has not been affected.

"We're doing everything we possibly can [to protect flocks], and we don't know of anyone who's doing anything we're not already doing," ­Spurway said. "The industry is lost for words."

Spurway said it's too early to tell if the outbreak will affect staffing at the farm.

Minnesota businessman Glen Taylor owns Rembrandt, as well as the Minnesota Timberwolves and the Star Tribune in Minneapolis.

As of Friday, the number of afflicted Minnesota farms had risen to 88, affecting 21 different counties, according to the Minnesota Board of Animal Health.

The agency announced Friday the cancellation of all exhibits featuring birds at the Minnesota State Fair this year to stem the spread of the H5N2 virus.

The directive also prohibits exhibitions at county fairs, swap meets, petting zoos and sales.

The ultimate source of the bird flu is believed to be wild waterfowl, but health experts are puzzled as to how exactly it's creeping into enclosed barns.

While it is deadly to poultry, the bird flu poses a low risk to human health.

Staff writer Mike Hughlett contributed to this report.

Liz Sawyer • 612-673-4648