Tampa, Florida - The dog shelter staff of the "Mercy Full Project" were shocked to see the contents of a large cardboard box. Countless puppies were crowded together in a heap!

"Shock doesn’t even begin to describe it," said Heydi Acuna, founder and director of the Mercy Full Project, in an interview with The Dodo.

"The moment we realized two moms had arrived with 21 tiny puppies between them, the entire shelter went silent. Then came disbelief, urgency and heartbreak all at once."

The 23 dogs had been brought in by a woman who had originally only accepted the two adult animals from her neighbor to look after.

The problem: the owner of the pups, who were still pregnant at the time, then disappeared, never to be seen again.

The completely overwhelmed woman was left behind and soon afterwards had to watch as first one and then three weeks later the other dog gave birth to their babies.

She tried to sort things out herself for a while, but after a few weeks, the unwanted dog owner gave up and contacted the Mercy Full Project.

After the initial shock, there was a bit of chaos at first, as the 21 puppies, who were three weeks apart in age, first had to be assigned to their respective moms, who were visibly overwhelmed and covered in fleas.

"Both moms were terrified... They had just been uprooted, surrounded by unfamiliar sounds, smells and people – while trying desperately to protect and care for their babies," Heydi Acuna described.

"The puppies were scared too, clinging to their moms, unsure of what was happening next."

Fortunately, calm quickly returned after the initial turmoil, as the stress levels dropped once the puppies were back together with their respective mothers.

"Today, both moms are doing beautifully," said Acuna.

"They’re finally able to rest, decompress and just be dogs – something they likely haven’t had the chance to do in a very long time," she continued.

"The puppies are spunky, playful, curious and full of life – exactly how puppies should be. Watching them bounce around, wrestle and explore feels like witnessing hope in motion!"

Some of the puppies have already been placed in new homes, while the others are still waiting for a family to give them a chance.