If your beloved pooch has lost the ability to use its legs, fear not. There are animal wheelchairs on the market, and the company that pioneered the contraption operates out of the South End.

And business is booming.

Freeland-based K9 Carts has made a name for itself in the animal care world by being the first company in the United States, and perhaps the world, to sell carts, basically wheelchairs for animals, according to owner Barbara Parkes. The company builds support chairs for pups, cats, mini horses and nearly any other animal imaginable that either was born with a disability or is losing the function of its legs.

The carts are constructed from lightweight material to help the animals maneuver without being dragged down by extra weight. Made primarily with metal, some plastic pieces and wheels that vary in size depending on the cart, the wheelchairs are constructed quickly enough that the company sells around 50-75 carts per week. Carts cost $225 for smaller carts, and extra large carts are $525. Rentals are available ranging from $75-$175 depending on the size.

It’s a service that South Whidbey, let alone Western Washington, is lucky to have when a pet starts to lose function of its legs, said Bellevue resident and customer Howard Eng. Eng recently brought Roxy, his 13-year-old Cavalier King Charles Spaniel into the shop since its little legs started to atrophy a few weeks ago.

“We’re just fortunate they’re here,” Eng said. “I read online they’re one of the top companies that do this.”

The carts are typically made for the hind legs of an animal, although the design team can make contraptions for front legs and full support carts. Parkes says her customers often regain the use of their legs, much to their delight.

Wheelchairs are highly customizable to the animal, and the company regularly builds new models for the more odd pets. Earlier this week, Parkes and her crew built a cart for a 90 pound turkey who fractured its legs after jumping from a dog house. The crew built a contraption that provides support from beneath the turkey that held it up but encouraged it to putter around with its broken legs.

The accommodation of even the strangest pets is giving K9 Carts an edge over their competitors — who else is building wheelchairs for massive turkeys? Parkes said there are companies based out of China and around the world who are mimicking her business model and trying to keep up, but she says the company’s solid reviews online and 40 years of experience are giving them an edge.

“It’s not just about selling a product, it’s about caring for the pets and the owners,” Parkes said. “I almost think it’s not a business per se, but a way for me to improve the lives of pets.”

So how does ordering a cart work with so many varying dog sizes?

K9 Carts requests measurements and history of the animal so they have a better idea of what to recommend. After they receive the measurements, the four in the shop design a custom cart from individual parts. The company then ships the wheelchair along with some extra pieces such as a sling and extra nuts and screws. Enough material is sent for the carts to be adjustable to fit the size of nearly any animal. Sizes run from extra small to extra large, accommodating both Chihuahuas and Great Danes.

Business has been so good for Parkes that she’s able to employ eight people — four in the shop, two in the administrative office and her son and his wife in Florida who help with designs. She also has a system of agents worldwide who send her orders from customers in their respective countries. Parkes said she has agents in countries such as the Netherlands, Japan and Czech Republic.

More growth is expected as well.

“We’re still on an upward trajectory,” Parkes said. “Glenn [her son] is designing a new website which will drive business. We also have an 800 number to call for customers around the world.”

K9 Carts has come a long way from its beginnings in Pennsylvania some four decades ago. Parkes, originally from Scotland, did administrative work for an animal hospital back then and witnessed countless animal surgeries. Her ex-husband was also one of the first veterinary orthopedic surgeons in the states, she said.

Parkes said there is a time limit for doing back surgeries for animals, particularly dogs, otherwise they would lose their mobility and drag themselves from place to place in a miserable stupor. Parkes went to a friend and handyman to build a wheelchair for the dogs, and she liked what she saw. She ran with the idea and started a business out of her garage and took it with her when she left for Montana before heading to Langley some years later.

Forty years has passed since then, and she still loves her job as much as ever.

“It’s so much fun, you get to talk to people from all over the country and often from around the world,” Parkes said. “I still get a kick when dogs run out the door.”

Since starting the business, Parkes has built carts for most kinds of pets, including mini horses, iguanas, turkeys and guinea pigs. For her it’s all about helping the animals and seeing the reaction from the owners when their pet’s mobility starts to improve in a single session.

“In the last couple of weeks, Roxy couldn’t even walk 10 feet without stumbling,” Eng said. “It still didn’t look good at the beginning of the session, but once they modified the cart she did so well. To see her do that again was great.”

Parkes said she should’ve retired long ago, but hasn’t yet because she loves what she does. Business is going well, she has a driven staff and new challenges arrive weekly with different animals with different mobility issues. It’s kept her going for 40 years, and she doesn’t plan on stopping yet.

“No matter how much you see, you always see something different,” Parkes said. “You never know what’s going to walk through the door.”