WESTBROOK — Jon Lawpaugh and Jen King knew they wanted an adult dog, one that was medium-sized and good with kids, happy to go camping but calm on a car ride.

They didn’t care what breed or color, just that it fit in with their family.

“It’s the personality,” King said.

The couple had wanted a dog ever since they got together but also wanted to wait until they had their own house and enough land. That happened last year, when they bought a place in Limerick on more than 3 acres, but their son, Emrys, wasn’t quite 2 at the time and they thought he should be potty-trained before taking on more bathroom duties.

Around the same time, Lawpaugh, a multimedia specialist at Idexx Laboratories, had to take photos for an event held by the veterinary products and services company, which invited animal rescue organizations to come to its Westbrook offices and offered to cover the fee of around $300 for any employee who found a pet to adopt.

When the time came for the annual event this year, their family was ready to take on a new member.

Lawpaugh and King didn’t tell his three older kids beforehand, because there was always the chance it wouldn’t work out. They sat through their second-to-last day in Waterboro schools, not knowing their household was about to grow.

With Emrys in tow, King and Lawpaugh showed up early to Idexx’s Experience Center on Thomas Drive, where tents were set up outside in anticipation of the furry guests.

The first to arrive were smaller and younger than what Lawpaugh and King had wanted to bring home.

There was a 16-week-old black lab-shepherd mix named Sampson, and Hazel Grace, a year-old miniature pinscher that wouldn’t get much bigger. Both were rescued from kill shelters in the South.

While Hazel Grace yipped and bounced beside them, pulling her pink leash taut, Sampson plodded in circles, letting himself be pet. From behind his father’s leg, Emrys peered at the puppy, whose eyes were on the same level as the squatting boy.

As other dogs arrived, Emrys’ attention turned toward them. He knelt in front of a female pitbull who nudged his face, knocking him to the ground. She had too much energy for their family, King concluded.

“Do you want to look at the black dog again?” she asked her son.

He ran back to Sampson and sat down in the grass beside him. The puppy nuzzled the boy’s face, then licked his ear, prompting Emrys to pop up and run away, squealing.

Two more puppies had showed up in a pen, the brown and black versions of the same scrunched face. Emrys stuck his nose up to the holes in the plastic fencing to get a better look.

Sampson, too, hopped up to the pen, sniffing his competition. He was social but not aggressive, Lawpaugh and King observed, as they passed his leash between them. They never even heard him bark.

Meanwhile, more employees had arrived, and they took their turns reaching down to stroke Sampson’s back.

King and Lawpaugh hadn’t wanted a puppy because they thought it would be too hyper, but Sampson’s demeanor was naturally calm. They looked at his paws and could tell he’d grow to be just the size they wanted.

When Sampson wasn’t getting attention from other prospective owners, King squatted down beside him and smiled into his eyes as she rubbed his face between her hands. She would spend the most time with the dog, so it was up to her, Lawpaugh said.

But when Sampson rested his muzzle on King’s knee, he made the decision for her.