BOISE — Up to 160 domesticated elk that fled an Idaho hunting reserve remained elusive as a helicopter, a fixed-wing plane and more than 25 state agents failed to locate any during the first day of an emergency hunt meant to keep the animals from mingling with wild herds.

"There's only two kinds of cover in that area where the elk are: grain fields and very thick timber," Idaho Department of Fish and Game director Steve Huffaker said Sunday, a day after the search. "We had a trained observer in the helicopter, and he said, 'We could have had 1,000 elk underneath us, and we still wouldn't have seen them."'

Huffaker hadn't yet been apprised of Sunday's progress by Fish and Game and the Department of Agriculture, in eastern Idaho near Rexburg. Some of the elk were rounded up by the owner Friday, he said.

"I just want them out of the wild," Huffaker said. "So, if he traps them, or we kill them, those are equally good options. We just want to make sure they're healthy, and to make sure they're really elk and not really hybrids."

The elk escaped before Aug. 14 from the Chief Joseph hunter's reserve that's owned by Rex Rammell, a veterinarian who charges guests up to $5,995 to shoot one of the large bulls he's bred to have enormous antlers.

Rammell didn't report their flight, as is required by law, said state officials including Gov. Jim Risch, who fear the animals might spread illness and hurt the genetic purity of wild herds — including those in nearby Yellowstone National Park, just 10 miles away.

Risch authorized the animals' "immediate destruction" Thursday.

He'd originally asked the Fish and Game Commission to open a so-called "depredation hunt" allowing licensed hunters and private landowners to shoot the animals. Commissioners opted instead to monitor the situation over the weekend. Huffaker said he's not ready to make a decision yet on public depredation hunts.

"The Fish and Game biologists and conservation officers, and (hunters) from the Department of Agriculture are very good elk hunters," he said. "If they haven't been able to find them, I doubt the general public is going to do a whole lot better."

Rammell's wife, Lynda, told The Associated Press that employees at Chief Joseph and others had rounded up about a dozen loose elk Friday evening. They're being held in a pen on private property. She said the family didn't report the elk because they didn't know they'd gone missing.

The couple, who according to the Chief Joseph's Web site charge $1 million for a membership in their hunting preserve that includes a site for a home, dispute that the animals carry diseases, and maintain their genetic quality is superior to wild elk.

Rex Rammell has tangled with the state Department of Agriculture in the past over its efforts to get him to tag his domesticated elk. His wife said he's being unfairly branded a rogue game farmer by state officials who don't like his operation.

"They've painted my husband as being a very bad person, and he's not. He's a very good person," she said. "As far as the gene pool, my elk are far superior to the wild elk. That's why every hunter in eastern Idaho wanted to shoot one when they thought the governor had allowed them to."

In 2002, Rammell persuaded the Idaho Legislature to forgive some $750,000 in fines levied against him as a result of tag violations. In the latest escape, Rammell has said his animals are tagged but may not have tags on their ears that are visible from the required 150 feet.

The Idaho Elk Breeders Association, a lobbying group for the elk-farming industry, said Rammell is not a member of the organization.

The group "strongly" supports Risch's move to kill Rammell's elk that haven't already been recaptured, it said in a statement.

Still, its leaders believe fears of the spread of diseases including tuberculosis, brucellosis and chronic wasting disease to wild elk, as well as concerns over genetic purity, are overblown.

"The animals in question or their ancestry were tested for genetic purity by a qualified laboratory and declared pure elk," said Gary Queen, the group's president. "There has never been a reported case of brucellosis, tuberculosis or chronic wasting disease in the entire state."