boney 3 yr old

Question
Hi, we bought a 3yr old great Dane a few months ago.  The breeder said to feed him once a day.  I'm afraid that he looks too skeletal so I've been feeding him more but no matter how much we feed him he never seems satisfied and never seems to gain any weight. Could this be because of worms? We made sure to buy the best food possible for him from the pet shop so I dont think its that.  Any advice would be very much appreciated.

Answer
Great Danes should never eat only once a day. He should be eating 6-10 cups twice a day. If he is skinny start him out at 3.5 cups in the morning and 3.5 cups at night, I would also add plain yogurt to give him some extra enzymes. What food is he currently on? It may just not be the right kind for him. Have you had him checked for worms? If not I would because worms will cause a dog to not be able to gain weight. Let me know what food he is on but I would first and foremost take a stool sample to the vet and get that tested.

I apologize for taking so long to answer, I usually do within a day but having a newborn doesn't allow me the time to sit down at the computer these days...