The article strangely doesn't say the dog's age. But it has a pic of him as a puppy in 2012, and says he was gone for 11 years.

Since the article was written in the last few days, that means that Forty-Cal was about 3 when he went missing, and was about 14 when he returned.

The article said that two dogs went missing from their backyard at once, and the other came back after a few weeks, so she thinks someone took them from her yard.

Presumably from his description as being friendly, he lived as a family pet for all these years, and then was abandoned.