Common errors about Antiquity

[Robert Vermaat]

Supposedly, there is a code connected to the position of the horse's hooves: two raised hooves (i.e. horse rampant) means that the rider died in battle, one raised hoof means that the rider died of wounds sustained in battle, and no raised hooves means that the rider died of natural causes. This is such a trivial example -- and demonstrably false, from the evidence of your own avatar, Jona -- that it may not be worth discussing (... though I wonder where it came from).

I've heard the story too, and have no clue about its origins either.

Here's a link with more information about horse statues and the position of the hooves with a conclusion: "the stone cold truth is that the facts don't support it".