i dont know anything about horses why did i scroll through this blog for so long. i have seen so many bad horses, what makes a good horse
Because it's interesting! Depends on the horse and what you want it to do. Overall basic conformation rules that apply to every horse:
The back should appear relatively level from shoulder to butt, with a slight dip in the middle. Too much of a dip is a swayback, no dip is a roach back, both are probably painful and bad. The shoulders can appear higher, but the butt should not be the obvious high point. There's some leeway on this last point for young horses who usually grow into it at least a little.
The neck should be a smooth line on top and bottom. It shouldn't appear to dip in front of the shoulders, and the horse should carry it in a smoothly arched posture while moving around, especially while moving faster than a walk. There should be visible muscle in the neck. It should be long enough that the horse can easily arch it enough so that the forehead is vertical. The head should never be longer than the neck, but in some heavy draft breeds and stocky ponies they'll sometimes look about the same.
All four legs should be vertical and straight when viewed from directly in front or behind. The joints should be as close to in line as possible. When viewed from the side, the long bones of the front legs should be in line above and below the knee. The knee will bulge out a bit, but any joint that looks abnormally large or out of line is an issue.
When looking at the hind legs, the long bone in the lower leg should be as vertical as possible, but this varies with posture. Judge this when a horse is standing calmly on level ground and bearing its weight evenly. The upper long bone in the hind leg absolutely should not be vertical in a neutral weight-bearing posture (when the lower bone is vertical). The closer to vertical, the more wrong it is. If it looks like the horse can easily bend and flex all joints in the hind leg, and the lower bone is often held comfortably vertical but the upper one isn't, you're good. If the movement, legs, and topline are fine, the hip is also probably fine, but you can get really technical with hip angles if you want. It should look like a triangle. Don't worry about it yet.
The feet should all be pointing straight forward, not facing each other or out. The pastern, the short bone just above the hoof, should be long enough to flex as they walk, but not so long that it looks like it's sagging. All four pasterns should be at about the same angle (though they can appear slightly more vertical in the back without issues) and that angle should match the angle of the base of the neck at the shoulder. This is a pretty easily visible line. Generally speaking, longer pasterns and a deeply sloped shoulder angle indicate smoother gaits and a more comfortable ride, and vice versa. Neither is necessarily more desirable, it depends on what activities you're doing. Steeper angles are better for jumping, for example, even if it'll mean a bumpier trot.
Overall, the horse should appear balanced and move freely. There should be visible muscle throughout the body and the coat should appear healthy. There's a wide range of acceptable body types specialized for different tasks, and the horse you choose should have a body type that lets it perform what you ask comfortably.
This is kind of off the top of my head but these rules should be pretty universal (and a perfectly achievable bar for any intentional breeding imo).
