I've tried trotting and walking and it works...sometimes.
You've got to make it work ALL the time. Never quit asking for her to do something until she does it properly. AKA, never end a lesson without you "winning". She if you want her to walk, but she wants to prace, well then guess what? She's going to prance and prance and prance until she finally gives up and walks. You need to have the patience and consistency to get the response you want.
Gidget is waaaay too hot. I have to hold her back or she will take off before I'm ready. She tosses her head if I don't let her go and I end up have to trot her in small circles.
Gidget has got your buttons. She's like a spoiled child that knows how to get what she wants. You need to not let her get away with it and you need to get control of her. Being "hot" has nothing to do with it. There is a huge difference between having a hot-and-out-of-control horse and having a hot horse that is attuned to the rider and ready for anything the instant the rider gives them a cue.
She should never be taking off running on her own without you cueing her to do so. If so, you should be circling her over and over until she stops and stands nicely when you ask.
Head tossing is never allowed. It's her throwing a temper tantrum and getting away with it. You should be using that snaffle bit to ask her to drop her head, give to the bit, and collect the rest of her body. You should be able to do this on a straightaway, although it is easier to teach going in circles. Do everything at the walk first, before moving to the faster gaits. Hold steady light pressure with both hands on the bit while at the same time lightly squeezing with your legs to drive her forward. Hold these cues steady until she gives you the right response (so do NOT squeeze or pull harder if she doesn't respond -- just hold steady). The very instant she stops fighting or throwing her head, release all your cues and allow her to walk on. That's her reward -- release of pressure. Then do it again. When she gets good at not fighting you, then start expecting her to actually drop her head a little. Keep your cues steady until she drops her head in the slightest bit. Then immediately release all your cues (reward). Your ultimate goal here is for her to collect, drop her head, and be soft on the bit whenever you give her that cue (light pressure on both reins and light pressure with your legs).
She sees those barrels and she just wants to go....I am not sure if this is bad or good. I am glad she wants to go but don't want any accidents or have her become a nut case in the arena...she isn't hyper any other time just when she sees them.
There's nothing wrong with her getting excited for barrels. If you watch a good barrel horse, they are excited and on the muscle and ready to go. However, you will also notice that a good rider is always in 100% control of that good barrel horse. They're just putting that energy and drive to good use.
As I commented on your other post, at this point, the way she is excited is a BAD THING because you are the rider are NOT in control of her. You need to slow things down, and do slow work to get control, collection, and calm from her. Based on the videos on your other post, you are well on your way to her being one of those nut cases unless you take things back a few steps.
If she's hyper anytime she sees them, then you really need to capitalize on that by NOT always running them. If you end up running the barrels every single time she sees them (even if after you've done slow work first) she is going to associate that. So some days, do ONLY slow work -- no running. And some days, work in the arena with the barrels set up, but don't actually do anything with the barrels. Doing something else in the presence of the barrels will help her to realize she only needs to get excited about them when it is competition time.
I feed her 1.5 lbs of alfalfa pellets a day. I have to feed her a simple diet because she colics all the dang time. I add her probiotics to this...I don't think this amount could make her hot.
While yes, their diet can clearly contribute to how "hot" they are acting, this is really irrelevant in my mind in this situation. Solely because YOU are letting her get away with bad behavior, so I see this are rider error, and not a problem on the horse's part. THere's nothing wrong with her being hot; it's what you do with it.
I am using a snaffle..I hate pulling on her mouth.I tried a curb bit and she still doesn't do well in it...she responds a bit better but I prefer to use something that is more lateral.
You should not have to pull on her mouth with ANY bit.
"The bit is only as gentle as the hands behind it."
If you cannot control her in a snaffle (which you clearly are having problems with), then jumping to a stronger curb bit should NEVER EVER even cross your mind. Using a harsher bit to cover up a training issue is always going to backfire in your face down the road.
Overall, I think you need to stop working on the barrels for a while and just work on getting Gidget more broke in general. She needs to be light in the bit (and so do you) and responsive to all your cues (hands, voice, seat, leg, etc) no matter what you are doing. I could ramble on about exercises and things you can do but I honestly think the best thing for the both of you at this point would be to work hands-on with a trainer.
There's only so much you can relay through a computer screen, that just doesn't cut it when it comes down to it.