You are improving, though as you noted, Barbaro's legs are far too long for his body, but you are getting better. To get even better, try working on one "part" at a time - do several sketches, including shading, based on one front leg and hoof, for example, make that the size of your page each time. Pay attention to how the muscles form shadows and highlights, and how the horse holds and bends that leg. Then do a hind leg for as many times, it's called doing "studies." You'll get to know the horse anatomy better, and you'll be surprised how much that will help when you then do a "whole horse" from scratch!