I don't think so - I think it's the angle of the photo - it's not a straight down view. You can see the walls on the 'top' side of the building, and not the bottom, so I expect the difference in width is a result of the angle of view (which I think places the camera some way off the top of the picture, so as well as looking down, you are looking down. erm, looking down from above, you are looking down the page, if you see what I mean).
On the other hand, having dissimilar sides to the roof could make sense - the ridge could be offset towards the open side, giving a lower back wall (cheaper to build), without loosing that much usable height inside. This would offset the hip at the end, but that would give it a nice 'feature'.
On a slightly different topic, consider carefully which wing of the building has the main roof - at the moment you have the cart shed roof being the main one - I would have expected the (fully sided) barn to have the main roof - it would be better able to support it...
I'm looking forward to what you can make of this Jason.