[Dc1011]

HI all:
I just wanted to post a quick question and see if any of you other yorkie parents have a response.
Dex is now a little over 8 months old and around 3.8 lbs.
Both of his parents were around 6 lbs and sturdy.
I have noticed in the last week or so that when I rub on his back I can feel his vertebrae? Is this a normal puppy thing? as in do they not "fill-out" until a little later in age. It seems that his growth pattern has been mostly growing in height first then in length...
He eats his food well and seems to be on a regular schedule. I am not sure if I should be feeding his more? I do not want to over feed him! When I put his food down in the evening he doesn't run over and ravage it or anything; he just simply eats a little then leaves and comes back and finishes it later. I am assuming he is getting enough food or would act REALLY hungry when I feed him??
Anyone have any input here?

Oh his feeding schedule is 2x daily once around 6:50 am (1/2 cup) then 1/2 cup around 6:00 pm