A Prince William County couple have won a reprieve in their battle to keep 35 pet ferrets in a large back-yard cage.

County officials initially had directed Irene and Leslie Wells to get rid of their pets because ferrets were considered farm animals, and the Wells' property was not zoned agricultural.

Last week, however, the county reversed its stance, reclassifying ferrets, small, weasel-like animals, as household pets, which are permitted in residential as well as agricultural zones.

In explaining the county's change of heart, Zoning Administrator Michael Congleton said the county had no experience with ferrets prior to this summer.

"At first blush," he said, "it appeared that ferrets might be considered farm animals, but then we did some more research, and we found we could consider them as household pets," he said.

"I think it's a big victory," said Irene Wells, whose ferret fight with the county began in early August, when authorities ordered one of her prized pets named "Occupant" killed and tested for rabies after it allegedly bit a child.

The pet's death upset Wells, who described Occupant as "a little doll-baby," whom she had lovingly groomed for a competitive match in North Carolina known as the Ferret Fun Festival.

Nor did she appreciate it when the county handed Occupant's remains to her in a garbage bag, and called a few hours later to say laboratory tests had proved negative. The ferret was not rabid, after all.

It wasn't until after Occupant's death that the county decided ferrets were farm animals and ordered Wells to remove her 35 other pets that she kept in a $200 "condominium cage" on her patio in Dale City.

"I think it's positively asinine," Wells said at the time. "Who ever heard of farm animals that were housebroken?" Her husband concurred: "We certainly can't plow fields with them." The couple considered filing a lawsuit.

Wells received her first ferret, Lady Weasel, as a $50 Christmas present from her husband several years ago, and it was immediate love.

"She was clean," Wells has explained. "She didn't have an odor, like people think they do. She washed herself like a kitty cat. She was just precious. She fit in my pocketbook. I took her to K mart, to Peoples Drug Store, into Zayres."

Wells also paid to have Lady Weasel bred. The baby ferrets, including Occupant, were born on the Wells' bathroom floor on March 19, 1983. "I helped deliver that ferret," she said.

Irene Wells has since become a ferret advocate and is credited by the International Ferret Association of Roanoke, Va., with developing through selective breeding a new official coat color: "chili-pepper red."

In mid-August, she was appointed the metropolitan Washington director of the International Ferret Association, a title bestowed in part, she thinks, because of the tenacity she displayed during the dispute over Occupant.

A lingering question, Wells said yesterday, is whether drug companies can be persuaded to develop a ferret rabies vaccine that will meet U.S. health standards. There is no such vaccine currently on the domestic market, and experts say little research has been done on how ferrets react to rabies.

Although Occupant had had a rabies shot of the sort given to cats, Prince William officials said they had no choice but to kill the animal and then test it for the disease. CAPTION: Picture, Irene Wells and some friends:"I think . . . (the reclessification is a big victory. By Harry Naltchayan--The Washington Post