The neck of the buck in the back of the 2015 picture merges with his chest above his brisket. His shoulders and hams appear developed, but not well developed. His shoulders appear much smaller than his hams. These observations may due to his posture and because his angling away from the camera. Based on this picture I estimate the buck is 3, maybe 4 years old. I’m leaning toward calling him 3 years old.