Oh me, here we go again, making carnivores out of our vegetation eating crits!! I hate that! I don't mean you, C4, unless you'd be feeding ye crits that ground up animal mess like they do with cyattle, thus causing mad cyow mess. Making cannibals out of herbivores - hey, it ain't right I tell ye. I done about thread jacked ye post!
Anyway, I'd say about 2 - 3 years for them. Deer antler is the fastest growing animal tissue there is, ye cain't go by antlers for age.
They look , 2-1/2 to 3-1/2, but sure have nice looking genetics (considering the drought the last couple years).