STx, I understand the neck meeting the brisket. Can you elaborate on what you look for at the top of the neck. Never really looked for that beyond loose skin under jaw and other characteristics of head itself. His neck "starting under jaw" as opposed to "staying up under throat" I cant grasp.
It was late last night and on meds for allergies or cold or flu of who knows WTF it is...so what I meant to type was "It(his neckline) stays up above his brisket where it meets his body" and not "It stays up under his throat where it meets his body." When the necks starts at the jaw it runs down towards the brisket...what it does when it get there determines age for. If it stay above the brisket he is 4 or less, if it runs straight from the bottom jaw to the bottom of the brisket he his 5+.
This is an example of a 4 yr old.
This is an example of a 5 yr old or mature.