Part of the issue is trust. Penny needs to be able to trust you in situations that she finds either life-threatening (trust that you're not going to put her in any danger or hurt her) or just plain exciting (where you need ''money in the bank'' so to speak to ensure that her attention stays with you). You need to decide which of the two it is: my pony has had (and still has relapses
) a complete terror of cows, so if a herd of cows were to run at him he'd be out of there! But with horses running at him, it's usually a case of wanting to show off and join in, although there definately are exceptions, some horses look plain scary galloping at you!. It sounds as though you have a pretty good relationship already, as you mention that other than this she is bombproof
.
In a scary situation, Penny feels that she HAS to move her feet. That's her survival instinct kicking in. Moving the feet only really becomes a danger when it is your horse deciding where to move them, so if she needs to move let her - but guide and support her at the same time. Gain back her attention, calm her down. Remain calm yourself (relax!). When she's relaxed you can stop her, ask her to stand. If every experience with this she has is a good one - no tense rider, no ''emergency stopping'' and plenty of praise - she can gradually overcome her fear. As much as possible, try to avoid any instinctive gripping and pulling back on the reins (and I know this can be difficuly) - mostly, that just raises the head which gives you results opposite to what you want!
Getting her to focus on you is something you can do at home, and well worth doing - considering your experience with the car it would not be a bad idea. I'm not sure I understand what happened there though - was being left behind the car the problem or were there horses/cows nearby that were moving?
If she's scared of cows full stop, depending on the intensity of her fear, would it be possible to keep her near cows or with cows for any lenght of time? The same with other horses - is she turned out with them or on her own? You could try riding in an arena or field with other horses as well.
If it's more due to excitement the same thing pretty much applies still: getting her focus back onto you ASAP. You can probably predict when she may become excitable, so can then work on keeping her attention. Get her to do things whilst hacking out so her brain is lept occupied - it's then also easier to get focus back that way if you do lose it.
Hope this helps you.
