The Horse Show Blog had an interesting post about hand feeding your horse. You can read it here as well as my comment ( I’m Laurie). I have always given my horses treats by hand after a workout and always taught my students the safe way to do it. So far, I’ve never had an overly aggressive horse because of it. If they were aggressive it was for other reasons.
I agree with Rick Lamb
“How do you get your horse to respect your space? First, you have to claim your space as your own and never, ever allow your horse to enter it uninvited. You must defend your space with whatever amount of energy is required to get the point across. And this is important: you have to be consistent. If crowding into your space is wrong today, it has to be wrong tomorrow and every day after that. There must be a negative instant consequence (a NIC, in Monty Roberts’s words) to that behavior every single time.”
He is absolutely correct about your space is yours. In the herd a horse only lets another horse into his space if the other horse is higher in the pecking order. A person in my opinion always has to be the highest in the pecking order. There is no other way.
He also is right about consistency. I always call it persistent and consistent. We can’t give up when we make a request and we have to always ask the same way.