Usually I say "hey" or "no" and give the horse a slap. If I'm walking them in a halter, I usually jerk the rope once. I haven't done the squeal thing, as I don't really know how. XD I think kicking should only be used for certain times. For a small horse or pony, no kicking should be needed, for a large or draft horse sometimes they need something that they can actually feel. I know some draft horses who have no reaction at all to a slap because of their hugeness. If a horse were to kick at me when I was walking behind them or being extremely pushy and not respecting my space, I'd give them a good boot, because that's what a lead mare would do.