"I see a lot of great dogs come through shelters, and they would be great candidates for a lot of sports. And sometimes they get overlooked because they're not purebred dogs," Campbell said.
Roo! will be one of about 225 agility dogs whizzing through tunnels, around poles and over jumps before the Westminster crowd. And, if she makes it to the championship, on national TV.
Animal-rights advocates call the development a good step, though it isn't ending their long-standing criticism that the show champions a myopic view of man's best friend.
Westminster's focus is still on the nearly 190 breeds three of them newly eligible that get to compete toward the best-in-show trophy; more than 90 percent of the agility competitors are purebreds, too. But Westminster representatives have made a point of noting the new opening for mixed breeds, or "all-American dogs," in showspeak.
"It allows us to really stand behind what we say about Westminster being the show for all the dogs in our lives" while enhancing the 138-year-old event with a growing, fun-to-watch sport, said David Frei, the show's longtime TV host.
Over the years, mixed-breed enthusiasts have nosed around for recognition for their pets, be they carefully crossed goldendoodles or anyone's-guess mutts. And they haven't turned only to gag events like "Great American Mutt" shows with categories such as "longest tongue" and "looks most like owner."
A 36-year-old group called the Mixed Breed Dog Clubs of America awards titles in various sports and has even had best-in-show-style competitions, where dogs were judged on their overall look, movement and demeanor, said President Kitty Norwood of Redwood, Calif.
Some dog organizations have allowed mixes to compete in obedience, agility and other sports for years, and the prominent American Kennel Club the governing body for Westminster and many other events followed suit in 2009. It has since enrolled some 208,000 mixes and dogs from non-recognized breeds as eligible competitors.
One of the nation's oldest sporting events, the Westminster show had a few mixed breeds in its early days but soon became purebred territory. This year, more than 2,800 pedigreed, primped dogs are set to be judged on how well they fit breed standards that can specify everything from temperament to toe configuration.
That has long made Westminster a flashpoint for the purebred-versus-mixed-breed debate.
Proponents say breeds preserve historic traits and help predict whether a puppy will make a good police dog or hiking companion, for instance, facilitating happy pet-owner matches.
Animal-rights activists argue that the desire for purebreds fuels puppy mills, forsakes mixed-breed dogs that need homes and sometimes propagates unhealthy traits. (The American Veterinary Medical Association hasn't taken a position on whether mixed breeds or purebreds are generally healthier.)
Westminster President Sean McCarthy says the club supports conscientious breeding and is "a big believer in dogs that are well cared for, loved and healthy," purebred or not. But to critics, the show spotlights a skin-deep appreciation of dogs while downplaying darker sides of breeding, and adding some mixed breeds outside the main event goes only so far.
"It's definitely a step in the right direction," says Daphna Nachminovitch, senior vice president for People for the Ethical Treatment of Animals. But there are better ways to help dogs than "supporting this antiquated entertainment show," she said.
PETA members have protested Westminster, once getting into the show's center ring with signs in 2011. The group plans to demonstrate outside the show this year.
Matt Bershadker, president of the American Society for the Prevention of Cruelty to Animals, hopes introducing mixed breeds at Westminster will lead emphasis "away from the aesthetics of dogs to what is special about dogs ... the very, very special connection that people have with dogs."
Irene Palmerini connected with Alfie, a poodle mix, when she spotted him seven years ago in a mall pet shop, seeming eager to get out of his crate. She wasn't looking for a dog but couldn't resist him.
Nor was she looking to take up canine agility, but he had energy that needed a focus.
Now, she's gearing up to bring Alfie to Westminster, with excitement and a bit of incredulity.
"I'm representing everybody who just sits on their couch with their dog," said Palmerini, of Toms River, N.J. "He's just our pet."
Reach Jennifer Peltz on Twitter at http://twitter.com/jennpeltz.