LOS ANGELES — Animal Planet will soon celebrate the success of a unique program aimed at second chance dogs, often shy and traumatized victims of puppy mills, hoarders and abandonment.

In an hour-long special, the network delves into the Behavior Rehabilitation Center at St. Hubert’s Animal Welfare Center in Madison, New Jersey. It’s a pilot program of the American Society for the Prevention of Cruelty to Animals that began in 2013 and will soon be expanded, in time for the ASPCA’s 150th anniversary.

Called “Second Chance Dogs,” to air April 16 (9 a.m. Eastern), the Animal Planet show starts at the center’s beginning, when the ASPCA decided to try rehabilitation for hard luck cases.

Of 259 dogs sent to the center since it opened, 185 have graduated. Of those, 170 were adopted and the majority is doing quite well, said Kristen Collins, a certified applied animal behaviorist who oversees the project and will be the director of a new facility planned as part of the expansion.

Not all the dogs were success stories. Thirteen were deemed inappropriate for the program, including those with health issues, and 28 failed to graduate after months in the program. Some of those were sent back to the shelters where they came from and some had to be euthanized.

But the ASPCA stands firmly behind the center. It will continue to move dogs through St. Hubert’s until a new $9 million, 35,000- square-foot facility is finished in mid-2017 in Weaverville, North Carolina.

“While we can’t yet answer all of the questions associated with rehabilitating at-risk animals, we continue to witness amazing transformations, dogs that conquer their anxiety and fear despite years of devastating behavioral damage. These transformations change the trajectory of their lives,” said Matthew Bershadker, president and CEO of the ASPCA.