RE: Age this deer
I would say 2.5 yrs.
His nose is a dead give-away to a 2.5 yr. old deer.. it's longer than an older deer. Notice the "beady" eyes which appear so large on the face. Again all signs of a 2.5 yr. old.
He does have a huge body for his age.. but neck is quite normal for a deer with high testosterone. I have a 2.5 yr. deer with a neck who would contend with any 4.5 yr. old.
I believe your assumption lungbuster on him being a 2.5 yr. old are absolutely correct.