I seem to be looking for some advice as usual. I have a pinto mare, farm horse used as cow pony\ cutting horse. More gathering than cutting. She's around eight to ten years old and wise to every trick in the book and then some. A little herd- bound as farm horses tend to be, but not unmanageable, I have ridden this mare myself back when I first moved to the farm and only had two years riding school once a week lessons behind me. Recently we decided to put her in a cross under BB,but Rainbow did not seem to like it much, so we went back to the bit. She is motmally ridden in a double-link copper snaffle with the lozenge in the middle, a nice thick mild bit. Today she went out to gather cattle and her rider came back complainiing she opens her mouth to apparently try and evade the bit. (I ride all my horses without nosebands so they show me if they have a problem) Now I'm left with one of a few options as I see it. Put a noseband on her, force her to keep her mouth shut. Try a different bit or a different type of BB. Her teeth were floated 5 months ago and were checked and given the all clear last week by an equine dentist. Or lastly a different rider. Her rider today is not the most skilled, but not the worst I've seen. Any other ideas or recomendations? Anything I'm missing?