Here is a handy chart I just found.  This is from a sampling of Eastern Wild Turkeys of known ages.  These are averages from the samples.

1 year old= avg. spur length = .26  beard = 4.44  weight = 15.5

2 year old= spur = .87    beard = 9.47   wt = 21.1

3 year old= spur = 1.01   beard = 9.46   wt = 21.9

4 year old= spur = 1.08   beard = 9.00   wt = 22.5

5 year old= spur = 1.16   beard = 10.93  wt = 23.8

Source:  www.wildturkeyzone.com