When Cherry, a black pit bull trained as a fight dog by former football star Michael Vick, arrived at the Best Friends animal sanctuary in Utah in January, he was afraid of everything.
"He was the only dog that would not walk on a leash," said Michelle Besmehn, the dog care manager at best friends. "He just flattened to the ground. We carried him in and out of rooms."
But now, after nine months of intensive training and therapy at the sanctuary, Cherry has become a playful, friendly dog that takes walks, plays with toys and doesn't even mind cats. And despite his inauspicious arrival at the country's largest no-kill animal shelter, Cherry could even one day be eligible for adoption.
"Cherry's next step will be to go to a foster home where he can learn real-life skills," Besmehn said.
In less than a year, Cherry, like the other dogs from Vick's fighting camp living at the sanctuary, has made huge strides -- and according to his caregivers, all it took was a little patience.
In 2007, 48 dogs were seized from a dogfighting training camp run by Vick, then a star quarterback for the NFL's Atlanta Falcons.
Twenty-two of those dogs were assigned to live at Best Friends, the largest no-kill animal sanctuary in the nation. The organization cares for 1,500 dogs, cats, horses, goats and other animals. With an annual budget of about $30 million, most of it from private donations, it has rescued animals traumatized by Hurricane Katrina and those who have suffered in hoarding situations or puppy mills.
Vick's former fight dogs live in a facility within Best Friends called Dogtown, and according to Besmehn nearly all have made major improvements since they arrived, both physically and emotionally.
"Everyone is doing really well," she said. "Physically, they seem healthy. They've gained weight. Some of them had itchy skin or the coats seemed oily and not right. Everyone looks really good.
"The dogs who are really shy are really comfortable with their everyday caregivers," she added. "Most are becoming more comfortable with strangers. ... We're trying to give them fun things to do that will also help them use their brains."
Adorable as these newly healthy dogs may look now, rehabilitating dogs that come from an aggressive and abusive environment isn't all rainbows and puppies, so to speak.
Georgia, one of Vick's prized fighters and, later, breeding dogs, arrived at Best Friends nearly broken. Scarred, toothless and broken-tailed, Georgia snarled at anyone who touched her food bowl or her toys.
"She had cropped ears so other dogs can't grab them in the ring," Besmehn said. "She's clearly had a lot of litters of puppies. ... She had no teeth. We took X-rays and it looks like they were professionally removed so they could breed her more easily. Looking at her you're like, 'Wow, you're a mess.'"
Now Georgia loves spending time with people and has gotten more comfortable with being around other dogs.
For National Geographic Channel, the resocialization process has just made for good television. The Channel's series "Dogtown," which is based at Best Friends, has been filming Cherry and Georgia, along with two more of Vick's dogs -- Meryl and Denzel -- for the past six months.
"Being the Mayo Clinic for dogs, they take the most difficult cases where dogs have no of hope of surviving," said "Dogtown" producer Chris Valentini. "They care so deeply about the animals."
"Dogtown" originally began documenting the work at Best Friends last year, and the three initial episodes were very popular, the producers said. Producers hope the episodes chronicling the Vick dogs will be just as successful.
"When you marry the science with the natural history and the emotional component, you have powerful television," said Valentini.
And like most television fodder, this has its own controversy.
Best Friends was criticized earlier this year when it took in the abused pooches.
"Definitely, there were groups that recommended that these dogs be euthanized, that they can't be rehabbed," Besmehn said. "For us, we've taken challenging dogs on a regular basis. We feel these dogs, at a minimum, deserve a chance. We've seen these dogs are doing really well with a little bit of patience. ... They can make progress. It takes time."
Animal behavior specialists tend to agree with that sentiment -- with a few caveats.
"You have to be ultra careful," said Dr. Gary Landsberg, an animal behavior specialist at the North Toronto Animal Clinic.
According to Landsberg, fight dogs have been trained to defend themselves from other dogs, something trainers and potential owners should keep in mind.
"That would be my biggest concern -- what happens if you take this dog into your home and your dog is threatened by another dog?" he said. "You have a higher chance that the dog might fight in that situation. ... Those dogs might be a little hard to rehabilitate."
Landsberg still believes a large part of how the dog behaves depends on finding the right home for pet -- and it will be harder to find the right fit for an abused pet.
"No one should consider a case without considering the household it's going into," he said.
According to Dr. Peter Borchelt, an animal behaviorist based in New York, the likelihood of a rehabilitated dog "snapping" is extremely rare.
"That's always possible because that could happen in just about any dog," he said. "It would be pretty rare in the average dog for something like that to happen."
But that doesn't mean that some dogs are beyond treatment.
"There are large differences in dogs and how they respond to stress or deprivation or abuse, and some dogs in this group -- a few of them were not salvageable," said Borchelt. "That meant the level was too high to even risk to even treat."
One of those dogs that won't be allowed to join society is Meryl, who was "sentenced" to live at Best Friends indefinitely because of her aggression.
Meryl was an aggressive barker when she arrived at Best Friends, but she's become friendlier and even plays with toys now.
"These dogs didn't know what to do with a toy and didn't know what a treat was," Behsmen said.
The sanctuary hopes eventually to put most of Vick's dogs up for adoption. One of its prime candidates is Denzel, who arrived anemic and with lifelong tick-born disease.
"I could see him sitting at home on someone's couch," Behsman said.
Until that day comes, Behsman just hopes that "Dogtown" will let people see that pit bulls aren't an inherently bad breed, despite the reputation they've earned over the years. Instead, people should realize that dogfighting is a real phenomenon.
"I really hope that people come away being more aware about what people do to dogs," she said. "These dogs deserve a chance."
ABC News' Susan James contributed to this report.