The way your horse holds his head speaks volumes about how he’s feeling. The higher it is, the more alarmed and prepared for flight he is. A horse needs to keep his head raised in order to focus on objects in the distance. He lowers it when he needs to focus on objects immediately in front of him. When a horse carries his head even lower, almost to the ground, he is at his most subordinate and relaxed.
Teaching your horse to lower his head and give to pressure while in-hand is imperative. Horses are a naturally “into pressure” species and need to learn how to come off pressure. By teaching them to lower their heads you are teaching them to trust you, rely on you and relax. Then they are willing to give up their form of defense – flight.
Take this a step further and create a horse who looks for your affection and seeks out the halter by lowering his head into it! While your horse is at liberty in an arena or RP environment, you are looking for him to offer to lower his head. Any attempt to do this should be rewarded by a release of pressure. You can do this by dropping your eyes to below his nose, slowing down your walk, or not moving your long line for a moment. If you inadvertently miss this gesture, your horse may refuse to cooperate. Remember to always reward his tries!