This story suggests the drone was being used to haze the horse, in
which case the horse jumping out of the paddock (and unfortunately
onto a post) is understandable and there may be culpability.
But another concerning detail is that the paddock is "so close to"
a working helipad, which is a no-fly zone. How close? Collision
with a drone could take down a helicopter and kill everyone inside
and possibly also others on the ground.