We ustah take all kinds of measurements on deer captures in texas, we measured stomach girth, length of the skull,width of the ear tips, how pronounced the roman nose was, the amount of loose skin under the chin,on the neck,between the front legs,along with jawbone age and overall facial and body coloration(graying of the face)...we took the weights as well but that was worthless for aging..i honestly think appearance,loose skin in the right places, and body types..combined with the jawbone is about the most accurate way you could do it..other than a known history with camera footage and on the hoof sightings. Which is how i aged deer most of the time...and when i aged deer..i never said hes 2.5 or 3.5...i always said hes 1.5-3.5,3.5-5.5,5.5-6+...cause past 6 years they are very hard to age without having the abouve criteria..and thats from me dealing with hundreds of deer and pulling hundreds of jawbones...and sorting and editing thousands of pictures..with a known age database with several years of history to look back at. All that said...i will shoot the fist spike that walks by me on public land with my recurve.🙂