I would be more worried about his front legs, he ties in beneath the knees and that right front pastern, eeeks. But, he is still growing. I just don't like that weak looking area below the knees, and yes Viney, he has relatively small hocks and quite a bit of length of leg below. Pictures sometimes, actually lots of times are distortions but I would like to see that in person. Also, they should stay off his back for a while.
"Nothing in life is to feared. It is only to be understood. Now is the time to understand more and fear less." Marie Curie