There are 5 ways to tell a turkeys age...
1) Tail Feathers: Young turkeys, from about 4-5 months of age until their second autumn, can be determined from older turkeys by the molting pattern of the large tail feathers. These feathers are called "retrices". These feathers are molted from the outside inward from both sides at once. In the bird's first fall and until spring, the center 4-6 feathers will be longer than the outside ones because of a partial molting pattern. By the second fall, the molt has caught up and the retrices will be all the same length. That is, in the first fall and the spring thereafter, these juvenile birds will show an uneven tail pattern when the retrices are spread out. The center feathers will protrude a few inches beyond the outside ones.
2) Wing Feathers: The outer wing feathers (9th and 10th "primary" feathers, counting from the outside of the wing inward) show a distinct pattern in juvenile birds as compared to adults. In the first fall, these 2 primary feathers are not replaced in the molt. They are pointed, dark near the tip, and show little or no white barring. In adults, in which these feathers are molted along with the others, the 9th and 10th primaries are rounded near the tip (or worn down, if from a strutting male) and have white barring all the way to the tip.
(3) Spur: For adult males, spur length is somewhat useful in determining age, but it is not an absolute character. Generally, a spur less than 1/2-inch represents a juvenile bird, with those 1/2 to 7/8 inch from 1-year-old birds, and those 7/8 inch and larger are from birds 2 years or older.
4) Beard: Beards may also show a differentiation by age, with 3 to 5 inch ones from 1-year-old birds ("jakes"), 6 to 9" from 2-year-olds, and 10" or larger from gobblers aged 3 years or more. The reliability of this aging method is also somewhat suspect, though, as beards often wear off or break.
(5) Leg Color: The color of the lower leg can provide a rough indication of age. Young birds have a considerable amount of dark pigment in the leg and foot scales, producing a brownish or gray color. As the birds age, this pigmentation is lost and the leg color turns more pinkish or reddish.
My Brother: WMB