I bought a new saddle for Ice. Its an Abetta trail saddle with semi-QH bars and a 6 3/4" gullet. When I tried to put it on his back without a saddle pad, it tanked forward and sat right on his withers. However, he is a TB with very pronounced withers, and is a little bit dished out behind his shoulders, but not a lot. Other than falling forward, when I pressed on the cantle to get it to sit on his back correctly, it fit well, there was almost space for four of my fingers in between his withers and the pommel, and besides at the withers, there was no bridging that I felt from the tree. When I put a pad on with the saddle, even without the cinch tightened, it did not rock from side to side and there was space for like two and a half of my fingers to fit under the pommel. The saddle pad I have is built up, so there were extra panels of padding at his withers, and it looked like it fit very well. Everything was very even and nothing tipped forward or back. I even put him in the round pen and lunged him with it, he seemed fine to move, although at first he was a little sluggish and seemed slightly confused by having to work with tack on! Although I didn't get on, I did put my foot in the stirrup, tried some pretend mounting and then laid most of my weight across his back, and he seemed okay with that.
My question is, when he put his head down to munch on some grass as I was walking back to the tie rings, it popped up a little bit in the back. Is that normal? Does that mean it doesn't fit? Obviously I wouldn't be riding him with his nose in the ground, but I just want to make sure everything works properly. I can get pics if needed.