HARRISBURG, Pa. - A show rabbit breeder in Pennsylvania is suing a French gas exploration company for using low-flying helicopters she said terrorized her prized animals, causing many to die and leaving survivors unable to breed.

Deafening noise from helicopters flying over Susan Knowlden's mountain home in Trout Run, Pennsylvania, in search of shale gas deposits, sent her skittish rabbits into a frenzy, she told Reuters on Thursday.

"It scared the you-know-what out of them," Knowlden said. "They hit the sides of their cages and trampled the babies. They broke their necks or backs or legs."

Knowlden filed a lawsuit this week against CGG, the French oil-and-gas exploration company based in Paris, one of many energy firms involved in oil and gas extraction in Pennsylvania's Marcellus Shale, a heartland of America's fracking boon. The company also uses helicopters that employ seismic equipment to explore for gas deposits.

The helicopters fly "treetop level" overflights despite assurances by CGG that a 1,000-foot no-fly zone would be observed, said Tom Waffenschmidt, Knowlden's lawyer.

"My teeth rattled in my head," Knowlden said. "They were less than 20 feet above my barn."

As a result, she said, she lost 168 of her prize breeding and show rabbits - more than half her animals, she said.

Some of the survivors were unable to breed, said Knowlden, who said the show rabbits' pure bloodlines go back 28 or 29 generations.

Her lawsuit against CGG in Lycoming County Court of Common Pleas, Williamsport, seeks unspecified damages. Breeders say setting a value on the animals is complex, but that a long, clean pedigree counts for a lot.

The company did not immediately respond to requests for comment from its offices in Paris, Houston, and Williamsport, Pennsylvania.