One adorable Chihuahua, who survived years of horror inside a puppy mill, finally found a new life of freedom with his rescuer.

Billy -- as he was named after the rescue -- was locked inside a tiny cage for so long that the metal bars actually rusted shut, according to the Daily Mail. When he was finally rescued and taken to a veterinarian, doctors declared him emaciated and reported that half his lower jaw was missing.

According to One Green Planet, Billy was rescued from a puppy mill in Jones County, North Carolina. When he had passed his prime for breeding, the mill owners had simply left him to die inside a cage.

Billy's adorable face and steadfast resilience, however, immediately caught the heart of his rescuer, Adam Parascandola, who adopted the dog after prying open his cage in March this year.

"When I got this little guy he rested his head on my shoulder and at that moment I felt responsible for him and responsible for making sure he was never going to have to suffer like that again," Parascandola told the Daily Mail.

Parascandola took Billy home with him and has been caring for him ever since.

It is uncertain how old Billy is, since dogs rescued from puppy mills often look much older due to the conditions they are forced to endure. However, Parascandola believes his new best friend is around 10 years old -- and feeling younger every day.

Since his rescue Billy is a happier, healthier dog.

"This little guy, despite all he had been through, really very quickly his whole personality came out," Parascandola told the Daily Mail.

After the puppy mill raid, two people were arrested and later convicted of 38 counts of animal cruelty. They were released on two years of supervised probation, during which time they are not allowed to keep animals, reported HNLV News.

Eighty eight other dogs and one cat were also discovered at the puppy mill.

Since his rescue, Billy and Parascandola have become the newest faces of the Humane Society's latest fundraising campaign.

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