Originally Posted by kitten_Val
Was always wondering... Are there any signs whether horse likes or dislikes the bit? OK, I assume head tossing means "dislike". Horse is quiet and relaxed means it likes the bit. Any other signs?
Gaping mouth, chin tucked too close to the chest/neck, head held high or high-ish with the nose stuck out, chomping/biting the bit, tongue over the bit, or head really low "rooting" can all be signs of mouth discomfort, which may or may not be caused by the bit type. Also if a horse is stiff when you cue with the bit or resists the bit pressure in any way (won't stop or stops too fast).
A horse that is happy with the bit will have a relaxed head and neck, "soft" mouth, may salivate, and responds appropriate to his/her training.