Before the assumptions start, note this is a sable - most likely working line
He has a lot of rear angulation, a shorter front arm, and flat to normal withers - all this combined gives his back a curve when he is bunched up because the front is down lower than the back - I see this in working dogs as they tend to have fronts that drop down because of flatter withers and short arms. He is a puppy and at an awkward stage - he will grow into himself, but will likely always go down in the front because of the short arm and withers.
robk: you are being a little more severe on your boy than you should be. The pictures are really not doing him any justice - I only used the last pic as it is the nearest to correct. He is only 2 and will continue to fill out and mature. He has a nice dark mask, dark eyes, good pigment, nice color. He has moderate bone, and could use more substance. Could use a little more masculinity, but he is still maturing. Are you hiking or swimming? A month or so beforehand, hike him uphill as much as you can and up his food to build up his chest, forehand, and rear.My dog is a working line and he has a curved spine. It is the one trait that I am the most critical of him. You can see pictures of him in this thread that posted today;
He is very athletic though and it doesn't seam to affect his ability to do anything. I am going to attempt an endurance test (the IPO AD) with him next week. We shall see then how he holds up. (and how I hold up for that matter )