Is my lab healthy

Question
I have a 9 month old silver lab. He is tall and lean.  SOmetimes I worry he is too skinny. I am feeding abut 4 cups a day.  Should I feed him more?
I can feel the top of his spine very easily?  Is that normal?  Should it be silghtly curved?

Answer
Hello Lnz and thank you for your questions,

Oh I so want a silver lab lol, They are very neat looking. Anyways four cups is plenty thou I have a strict feed as much as they want policy for puppies under a year old, on another note your labrador retreiver should be on puppy food until he is 14 months old. Some labs are taller then other some are stocky some are slimmer built, I've seen labs on the internet like your discrubing but those are normaly from hunting lines. THe spine would be slightly curved over the back because of the dogs shape, If his weight is leaveing you worried and his ribs can be visably seen go to your locale vet and do a stool sample and get some deowmrer... worms make a dog thin also you may never know the dog has them until you see the dog get thinner and thinner.

Best of luck to you.