What are the signs of a healthy horse?

A healthy horse should be alert and recognize what's going on around him. His eyes should be clear, and have nothing oozing from them. He should be able to open and close his eyes easily. His nostrils should be clear and free of discharge. His ears should move around, to wherever he hears something interesting. His ears shouldn't have mites or warts inside them.You should be able to feel his ribs when touching his barrel but you shouldn't see them. If you can see his ribs clearly he is too skinny! If you touch any part of their body, including legs, the horse shouldn't flinch. His legs should not be hot or swelling. When walked in-hand the horse should have his weight all four legs evenly, and shouldn't be limping or dragging any feet. His coat, mane and tail should be shiny and even.
You can tell a horse's health not only by looking at him and touching him, but also by observing. A healty horse will eat and drink willingly. (They don't have to drain the bucket, but they should be drinking.) If he shows no interest in what's going on around him, he may be sick.
One of the best ways to tell if a horse is sick is to remember how he acts usually (eg., how much he drinks, how energetic he is, ect.) and then compare it to how he is acting on any particular day. These are some other signs.

• your horse looks alert,with ears pricking.
• The coat is glossy and lying flat.
• The horses skin is loose and supple.
• No signs of sweating when having a rest.
• Eyes open and birght.
• That there limbs and joints don't have any swelling or heat.
• That they stand evenly on all of their 4 legs.
• Breathing at rest should be easy not noisy or laboured.
• Temperature should be 38.5c
• Eating and chewing normally.

So that's some of the things of a healthy horse/pony if some of theses things are happening to happend to your horse/pony i would get a vet check to look at your horse/pony.