Food Related Anxiety and Over-excitement
Most horses start out at least a little thrilled about the clicker training experience. Teaching a safe, alternate behavior to mugging, such as stand facing forward, is a fantastic way to keep us safe and help the horse learn to relax around food. A key element in this first behavior MUST be relaxation. A horse can tuck their chin or look away or stand facing forward, but be boiling over, trembling with excitement.

What’s wrong with too much excitement? We want them to be happy, don’t we? We want our horses focused on learning, thinking, processing, seeking, and trying new behaviors. This can’t be done when the horse is over-threshold in any direction; fear, anxiety, or excitement. What if getting relaxation isn’t so easy? What if our horse is more extreme than “most”, and we can’t find even a moment of calm behavior to reinforce?

One of the most important changes is to NOT start a training session unless they are calm. Starting a session while the horse is at the door, buzzing and pawing and tossing his head, would only reinforce this behavior. Instead, start while the horse is eating hay or otherwise “being a horse”.
Additionally, find times throughout the day where he is off being a normal horse; eating, drinking, napping, hanging out, and toss him a big handful in his bucket, then keep moving. Catch him doing things you want to see more of, and reinforce those. This is one part of helping him realise that treats/reinforcers will come when he’s behaving in a normal, calm way – that he doesn’t need to get wound up and start throwing behaviours at us for that to happen.

Training with a barrier between you and your horse (protected contact) is often a good idea, especially if he already has a habit of mugging or a history of aggression. It’s still just as important to make sure you don’t trigger the anxiety in the first place – if your horse becomes frustrated or anxious, do something to help him out; don’t continue on just because the barrier is keeping you safe from his behaviour.