The balance issue I think is a combination of the right leg and the tail feathers. In the ref, a close look reveals that the top half of his leg is actually visible, angling down/left, and then the red part of its leg of course is very clear. Clarifying the top portion of the leg might help that.
Also note the distance between the leg and tail in your painting; they're closer together in the ref, so the leg looks more "under" the body, with the obscured leg looking more centered too.
Easy fixes for sure, and an interesting bird! I'd not heard of the silver pheasant before. I thought it was going to be an albino Chinese pheasant