I found a good "POP!" when my mare is in heat is enough to snap her out of her bitchy-ness.

When I found out how hormonal her dam is (crazy mare would break down fences to get at studs), I made sure to work very strictly while she was in season. Instead of asking, suggesting, telling ... I ask then tell. (for example, to go forward: seat, calve squeeze then spur for normal days; but seat then spur for in season).

I tell you what, I've never had a better mare in season. I even look forward to her cycle because she's more up to any task ... however, she is more easily frustrated so I stay away from teaching new things.

Of course she still has her kooky moments, but if I keep her moving and make her work, she generally stops fussing.

So in short, I'd try to build her work ethic while in season. Think about it ... you'd be upset to if all you wanted was ... you know. So, let her take out that frustration on some exercise. (maybe keep kid away from her until a good work ethic is formed?)

This probably can't be done with every mare ... but I'm a solid believer in it. Especially when I look at the difference between my mare and her crazy dam ...