He has plenty of pasture to run on, 60 acres of hills, streams and trees to play in. He's gotten a little pudgy, everywhere. There is a little fat build up around his doc, his ribs have a nice layer over them, you can still fill his ribs but you got to push a little. He looks fine, he looks like he's got his winter weight on but the only thing is, his withers are really bony looking? He's never had that problem before, he's always had nice withers, but on the top of the wither, the bone is completely visible. I'm shocked, the rest of his spine isn't showing. Is it just from lack of muscle or is it something else?
He just got wormed yesterday but before that he hadn't been wormed in four months. He was wormed with Ivermectin last and then Safeguard this time around.
Edited to add
He is a six year old quarter horse gelding.