He is almost three and has much energybut he just does bulk out like the two female danes we have what is the propblem? I can see all his ribs.

Some dogs have a harder time gaining weight.

How much are you feeding him and what kind of food are you feeding?

I would up his food to maybe three cups twice a day with half a can of wet food twice a day and see if that helps. Also get a high energy diet, its higher in protein and fats.