Not that I am any expert of such things but I am
agreeing with Chris' response to this. I think that Tom Thumb bits are
great, in the right hands...Its funny, I have heard folks refer to them as a
mild transition from the snaffle to a leveraged bit...I have to disagree with
that from personal experiance.
I hate to say it but I have a tendancy to
use and rely on my hands a little too much and this type of bit and me are
not a good match. Hey none of us are perfect, right?!
Try going back to the basics on a loose ring smooth snaffle or even a french snaffle.
Get her to give to the bit, give and release, give and release...lots of one
rein stops and starts. And praise when she does good...sometimes folks
don't think these horses need praise when they do good and that your release of
pressure is reward enough.
Get her to respect that give and take.
Use this technique with small 1/2 halts and try and get the response you desire,
then go back out on the trail if she is being respectful of the
requests.
If this doesn't work then I would get her teeth
checked. Actually even if this does work you should get her checked
out....especially if you have only had her a few weeks and don't know her
history.