My dog is 17 weeks old. The past 3 weeks I’ve noticed his back Hocks turning in when he walks. His hind legs are huge, 12 inches long and have always been very big in compassion to his body. His paws are huge. Now there’s a curve in his lower spine, not sure how concerned I should be. My vet is “waiting on a second opinion”, she was not sure what to tell me. Should I start him on a supplement? Limit his walking? I was feeding Nutrience sub zero for a couple weeks as it did say suitable for large breed as per AAFCO l but just switched to RC puppy German Shepard.