We just got a puppy. We've had him for three days now. We noticed his lowest joint on his front left leg gives out on him quite often. I have checked and he has no pain at all in the join. I thought maybe it was just the fact that he is a puppy and the muscles aren't developed enough yet. Is this something others have noticed. We are taking him in at the end of the week to get shots but was just looking for a little reassurance. Thanks