From shelter pup to service dog

David Herrin and his service dog, Preciosa, are together 24/7. She is completely attuned to his body. She can detect the slightest drop in temperature, change in smell, or irregular heartbeat and give him a signal that a seizure is imminent. Preciosa is David’s lifeline.

However, she almost didn’t get the chance to do this important job. Preciosa could have become a statistic when she landed in a city shelter. Luckily, the shelter is one that has partnerships with other animal welfare organizations, such as Best Friends. That’s one of the most important ways that shelters across the country have reached no-kill — by working together to save pets who need extra time or care. Arrangements were made to bring Preciosa to the Best Friends Pet Adoption Center in West L.A., where the next chapter of her life would begin.

From the start, it was clear that Preciosa, a 2-year-old Belgian Malinois, was not only stunning but also highly intelligent. The Best Friends team made it a priority to keep her brain engaged. “Preciosa was given in-kennel enrichment, such as food puzzles, snuffle mats, and Kong toys,” says Brittany Thorn, executive director of Best Friends in Los Angeles.

Despite her potential, Preciosa had a long way to go. She was mouthy and pulled when she walked on a leash. She also started jumping, spinning, and digging whenever she was confined for any length of time, which told staff that she was feeling stressed. To harness her strength and her smarts, the team created a specialized training plan for her. Preciosa excelled, picking up skills with ease. This star pupil was eager to learn and eager to please.

[From rescued dog to service dog]

During her time with Best Friends, Preciosa lived with foster families. Once in a home setting, the foster volunteers got to know the real Preciosa, each describing her as playful, affectionate, and, of course, remarkably smart. This active girl was always ready for adventure, but she was just as interested in lounging around. (Preciosa does this thing where she lays her head on your lap and bats her eyelashes up at you — it’s irresistible.)

When each foster stay came to an end, Best Friends staff knew more about Preciosa than they did before, and she would return to the pet adoption center. Like many dogs, she just didn’t thrive in a kennel environment, no matter how much love and enrichment she received. She’d start barking and jumping, which didn’t display her true self or appeal to prospective adopters. “Preciosa had the chance to decompress in foster care,” says Brittany. “She did great, so we knew she just needed out of the kennel environment.”

She needed a family as soon as possible. Then, finally, along came a potential adopter who was looking for all the qualities Preciosa had in spades.

Several years ago, a severe car accident turned David Herrin’s world upside down. “I had to learn how to walk, talk, everything all over again,” says David.

Doctors suggested a service dog, which led David to Zack, an incredible pup who brought him back to life. Through working with Zack, David developed an interest in dog training and began studying to become a trainer himself. When Zack died of cancer, David vowed to honor his best friend’s legacy by training dogs in shelters to become service animals for other people in need.

“I promised that I would spend the rest of my life trying to save dogs, working with them and training them,” he says. “A lot of people who are disabled have trouble affording a good service dog.” Depending on the needs of his clients, David teaches dogs tasks like retrieving items, opening doors, and providing mobility support.

As part of his professional studies, David took an online canine behavior course taught by Brittany, and the two stayed in touch. Years later, when David was looking for a new service dog to train for himself, he asked Brittany to let him know if she had any dogs who fit the bill. He needed someone loyal and intelligent with keen senses and a desire to serve.

Brittany knew just the one.

She immediately sent Preciosa’s pictures to David. As they say, it was love at first sight. “When I saw her photo and I looked at her eyes, I knew that she needed someone who was going to love her unconditionally,” says David.

Within days, arrangements were made to bring Preciosa to Georgia, where David would pick her up and bring her home to Florida.

When David finally met Preciosa, their connection was instant, just like when he first saw her photo. “She sat in the backseat with her head resting on my lap. (She was) very loving and trusting,” says David, recalling the ride home.

After they arrived home, Preciosa quickly bonded with David’s family, which includes his fiancé, his mom, and two dog friends, Dexter and Sanji. She fit right in with the pack.

Straight away, Preciosa and David began their training, spending every moment together. Preciosa began to tune in to everything about David’s body.

“I have heart issues, so she’s learning that rhythm of my heart,” he says. “When (people are) fixing to have a seizure, our body temperature changes. We put out a scent that dogs can smell when we’re fixing to have a heart attack.” If Preciosa senses something is off, she’ll bump David’s leg or pull at his chest to alert him.

[Faces of No-Kill: 3-legged dog earns her military stripes]

Preciosa makes everyday life possible for David, accompanying him to medical appointments, stores, restaurants, and more. David is beginning to have mobility challenges, so they’re working on getting her used to his walker. She provides crucial emotional support, too. “When I'm having a rough day health-wise and I’m going to lay down, she's the first one in the bed,” says David.

While Preciosa takes her role seriously, there’s still plenty of time for play. "We have more fun than we have work, just put it that way," says David, who describes Preciosa as a clown. “Here's the difference: When she has her vest and certain harness on, it’s work. As soon as that comes off, it's let's be a dog.”

So what does fun look like for Preciosa? She loves playing outside with her canine housemates. On steamy Florida days, David will set up games like hide-and-seek inside the house to keep the pups entertained. Her favorite place to visit? Starbucks for a pup cup. She has an adorable head tilt that makes every barista smile.

Brittany says that the bond between a person and a pet, like the one David and Preciosa share, is what makes her job worth doing. “It feels like kismet!” she says. “They are such a great match, and it makes me feel like every dog is just waiting for their right person.”

Today, Preciosa continues to help David navigate new challenges, and David remains committed to rescuing and training dogs from shelters for people with disabilities.

“If we’re saving the dog and we’re saving the person, that’s a double win,” says David, who has trained five new service dogs this year alone.

Preciosa’s story is a testament to the transformative power of animal rescue. While not every pet will become a service animal, every pet has the potential to change a life.

Our goal at Best Friends is to support all animal shelters in the U.S. in reaching no-kill in 2025. No-kill means saving every dog and cat in a shelter who can be saved, accounting for community safety and good quality of life for pets. 

Shelter staff can’t do it alone. Saving animals in shelters is everyone’s responsibility, and it takes support and participation from the community. No-kill is possible when we work together thoughtfully, honestly, and collaboratively.