She asserted herself as lead mare and you missed it. Little by little, she "pushed" and you saw it, but you didn't SEE it. I'm sure glad that she didn't bite a hunk out of your face. By comparison, a black eye ain't so bad. It was a wake up call, glad you answered the phone! LOL The REAL Lead Mare just woke up and is slapping the herd back into shape.
My 32 year old Tennessee Walker mare Sparkles, is, and always has been the Lead Mare. Horses have came and went, only one time was she challenged, by a 17 hand, built like a tank, big bossy mare named Rocki. Sparkles went after Rocki, teeth bared, head snaked out, ears back, whirling around to kick and driving Rocki away. Again and again, and again. I fed Rocki well away from the herd, but Sparkles ran Rocki away from her feed and wouldn't let her eat. I turned over a bucket and just watched it all play out.
@Bruce, horses never pick up a 2x4 and clobber each other, only ignorant idiot people do that because they don't speak "horse" and are too stupid to even try.
@thistlebloom speaks horse fluently and knows how to get Syringa's attention just like a lead mare, but without biting and kicking. A mouthful of hair probably wouldn't make much of an impact anyway, except on thistlebloom. LOL
So when a member of the herd needs correction, the Lead Mare chases that individual away from the safety of the herd. Being a prey animal, a horse alone is vunerable to predators. So when Sparkles ran Rocki away, Rocki desperately wanted back in the safety of herd. She could have gone anywhere on 36 acres, but suddenly, the 20 feet or so of proximity to the herd became the most important desire of her life. Sparkles didn't let up, chastising Rocki again and again, it went on for a couple of weeks. Rocki finally submitted to Sparkles and was allowed to join the herd. Thereafter, it only took an ears back, nasty bite or two for Sparkles to keep Rocki on her best behavior.
Syringa has had a bad attitude, with her ears back, swishing her tail, (think an eye roll from a rebellious teenager) clearly telling thistlebloom that she was complying, but didn't WANT to and it was only a matter of time before she challenged the Lead Mare for position in the herd. What thistlebloom is doing now is making Syringa "move her feet". Even in the confines of a pen, she is running Syringa away from the herd. Because she is in a pen, she can't run away, but must keep moving. As long as she has a bad attitude, thistlebloom makes her keep moving. When she changes her attitude, ears up instead of annoyed laid back, her reward is to stop. That is the pressure thistlebloom is talking about.
I hope you have a better mental picture of why posture, tail swishing, ears alert or laid back makes such a difference. That is horse language.
Thistlebloom I hope I have explained that correctly, feel free to add to or explain it differently.