Horses need to stand. If they lie down, it cuts off blood circulation and can stop their organs from functioning. For a horse to stand, they need to distribute their weight evenly on all 4 legs. If they put too much weight on one leg, they can develop injuries like laminitis which is what Barbaro died of. You can put a horse in a sling, but it creates the same problems as having a horse lie down. In Eight Belles' case, she broke both of her front legs. A horse puts 60% of its weight on its front legs. If she had broken only one, she could have stood on her other front leg, but to break both left her without any front legs to stand on comfortably. To ask her to stand up after she had fallen down and broken both of her front legs, would have been too much to ask. It would have been tremendously painful. If a person breaks a leg, you can put them in bed, but you can't restrain a horse and keep them lying down. A leg injury to a horse is extremely serious, much more so than a leg injury to a person. It's a shame that the magnificent animals weren't built with stronger legs and it's horrible to lose a horse as wonderful as Eight Belles. She may have had a rough start in racing last year (it took 3 tries to break her maiden), but she really turned into a top notch horse and I'd put her up there with Ruffian. It's just such a tragedy.