Plymouth: It’s a rock. It’s a car. It’s a dog! Two years old and a Collie, Plymouth ended up at the Aiken County Animal Shelter in South Carolina on September 28th. He arrived as a stray, along with Alyssa, a one-year-old Collie. With both dogs heartworm positive, their odds of getting out of this high-kill shelter alive were greatly reduced since heartowrm positive dogs cannot be adopted out to the public and come with a sizable medical commitment cost for rescues.