Seventy-two male beagles raised in a Spanish laboratory recently saw sunlight — and experienced freedom — for the first time, thanks to Animal Rescue, Media & Education (ARME) and its Beagle Freedom Project.

Watch below as nine of those beagles are introduced to grass and sunshine after living their entire lives in metal cages inside a research laboratory.

The recent rescue of 72 dogs, the largest in ARME's history, ended with 40 of the beagles arriving in Los Angeles, ready for adoption.

"We've been told they lived one per cage in rooms of 10 beagles, but they never had any physical interaction with one another," ARME spokesman Gary Smith told NBC.

Because they can adapt to caged life and are inexpensive to feed, Beagles are often bred for lab testing of household, pharmaceutical and cosmetic products.

"When the beagles are no longer needed for research, some labs contact organizations such as ARME, who then work to find good homes for the dogs," TIME's NewsFeed reports.

Since their rescue, 32 of the beagles, all of them between the ages of 4 and 7, have found loving foster homes in Europe. The other 40 dogs recently arrived in Los Angeles where they've been put up for adoption.

"Beagles are incredibly sweet, docile, companion animals," Smith said.

"The downfall is, the same reason the beagle is a perfect companion animal, is the same reason they're used for testing."