The average life expectancy of a cocker spaniel is 15 years, but this old guy would have been 17 on June 12th, but today we had to put him down. He had a a bad bad bad heart, in which was deteriorating the muscles of his hind legs, so he had a tough time getting up and around the 4 younger dogs. Even in his old age he felt like he could do his job of protecting you, even though he couldn't move very fast. Worst of all he was losing his body functions. He was around a long time, and he will be greatly missed.