Limping and rear foot dragging

Question
We have an almost 6 mo. old GSD. A few weeks ago I noticed him limping ( front right leg ). He has been in a concrete floor kennel since we got him. Only is let out at 5am and 6pm for food and exercise ( 1 hour + or - ). Took him to vet a week ago for ortho exam ( bending joints checking for flex. and pain ) no pain found. Vet prescribed Rimadyl said to come back in two weeks. I have also noticed a slight toe drag on rear left while walking. He seems healthy and happy.

Answer
Rimadyl seems strange, but maybe the vet thinks he is expending too much nervous energy.  Is he at home all day alone?  perhaps he needs more stimulation.  Could you find a professional dog walker to give him a mid day break?  Doggy day care is a great idea too.

I would get him off puppy chow to slow growth and give his joints more time to develop.  Most supplements do more harm than good.  Just feed him one of the common brands of adult dog chow, best the same protein source he has always had.  I know for a fact, that German Shepherds puppies do very well on Pro Plan and Iams adult chow.  There are thousands of X-rays to prove it.  Likely they do just as well on other common brands.