imagine the faces of them when they are instantly zapped from some unknown force; without warning or reason. They may buck for some while, run, but it the end just go back to eating grass and shitting. Then ZAP hahaha endless fun for the whole family.
i like the way its a remote control zapper, so you can control the zaps at your own leisure
let the horse get close .. thinking he is within range of the plants, then zap the fucker
you could even turn it into a game of sorts lots of potential imo