A 5 yr. old turkey is ancient but possible. It seems to me the easiest way is by looking at the spurs. A jake will just have a bump. a 2 yr. old about 1/2 to 3/4" long, a 3 yr. old an inch or so, and pointed. 4 yr. old 1 1/4' - 1 1/2" and usually needle sharp. 5 yr. old, longer than that.