A few days ago, I was writing a second critique (at the artist's request) on a colored pencil piece and started getting philosophical about how you should look at horses (or whatever your subject is) in order to portray them in art. At one point, I said, "Sounds like I'm starting a blog post," so here I am, writing that blog post.
When you paint, draw or sculpt something that's alive and you want it to LOOK alive, you need to represent it as accurately as possible. I'm not saying all art has to be realistic, but if you do something that looks at least somewhat realistic, then the joints and muscles should be in the right placement and position for whatever movement is going on.
"Reflection" (cold-cast porcelain, shown above) certainly isn't built realistically. The structures in the head and neck are exaggerated or stretched to make the piece an impression of this horse. Those who know this horse (Reg. name, "Rusted Spruce," show name when my daughter had him, "Imagine A Legacy," barn name "Stretch") recognize him despite his being stylized. That was my goal, to do a recognizable portrait yet make it unique in its style. And yes, I realize there are errors in this piece, but it was also one of my earliest sculptures, so I was still learning my craft. Yet despite its flaws, it's a lovely piece, has won awards and sells well.
Too many artists depend only on pictures for reference. That's fine, but you also need to learn about the subject, whether it's a horse or a human or a cat or a raccoon - whatever it is, it has a particular way its eyes are set (for instance). Horses, being prey animals (dinner for other animals, in other words), have their eyes on the sides of their heads so they can see behind them as well as in front. When a horse is grazing, he can see 350 degrees around him. A predator has his eyes on the front of his face, like a human, a dog, cat, lion, raccoon. These are species who chase down other animals to be their dinner. Their range of vision is much smaller than a horse's - 150 degrees for dogs and cats, and a smaller range for humans since our eyes are set more to the front of our heads than they are on dogs and cats. (Ref: http://www.mini-horse.org/vision_range.html)
My husband was standing just a bit to the right of center (as he faced my horse Ricos) when he took this photo, which is why the right eye looks bigger than the left. You need to pay attention to these distinctions when using photos for reference.
You may not be able to see the chipmunk in this sculpture since the photo's small, but this cougar, a predator, has his eyes on the front of his head. The chipmunk, a prey animal, has them on the sides. (The chipmunk's on the rock near the bottom and just left of center in case you haven't found him yet.) This piece is "In the Wind" and is a bronze. All the art shown here is mine, BTW.
Each species has a particular way of moving. Horses have four legs, but they don't move the same way cats, dogs or armadillos do. You need to understand the pattern of footfalls for each species you portray, and in the case of many animals like horses and dogs, you need to know how the breed you're portraying moves. A dressage horse moves much differently than a Paso Fino, for instance. A Chinese Crested moves much differently than a German Shepherd. If you don't have a clear understanding of such things, you may make a bronze or a painting that will last for years and years but is portraying an inaccurate movement, inaccurate tail carriage, the wrong shape and attitude of the animal's ears, etc. People who know that kind of animal will look at the artwork and shake their heads, wondering why you didn't do enough research to know how much weight that leg should bear at that point in the stride, why you have a Quarter Horse doing a pace instead of a trot, why your Chinese Crested isn't doing a prancing trot, why the German Shepherd isn't built with his haunches lower than his shoulders, etc.
"Presence" (Bronze, above) has lovely clean legs. It would be easy to run your hands over them to learn their structures. Before you start working around the back legs of a horse you aren't familiar with, ask the horse's handler to hold the horse's front leg up to keep the horse still and protect you from being kicked. Then gently run your hands down his legs, learning the feel of the muscles, tendons and bones and how they work together. Be sure to cup your palm over the hock bone itself - that point isn't sharp nor is it small. It's a big, wide bone that will fill your hand. Remember that when you're portraying it.
Once you've run your hands over his legs, if you're a 2-D artist, sit at eye-level to the horse's hocks, but far enough away that he can't kick you, and draw his leg, paying close attention to the joints, muscles and how everything's tied together. Have someone lift a back leg and run your hands over that hock joint and the pastern when they're bent, then sit down and draw them. Do the same for the front legs. If you're a sculptor, do a quick sketch in clay of the leg you're studying. You'll be amazed at how much this exercise improves how you portray legs.