I chalk this behavior up to two related factors: 1. She'd rather be in the pasture than working with me. 2. She is more concerned with her herd relationship with her pasture-mates than she is on the herd relationship between me and her (she forgets I'm boss). I have investigated physical reasons too but there doesn't seem to be any issue on that side of things so I'm just calling it pasture sass.
I know a few people who elect to keep their horses in pens in the summer because they notice a similar pattern if their horse goes out to pasture and they don't want to deal with it. I am not one of those people. My thought process is that I ride only recreationally, and my horse has to be in a pen or pasture for far more hours a week than she is with me, so I want her to enjoy that part of life. Her pasture is a pretty nice place to be if you're a horse: about 120 acres of grass to run and graze, 2-4 friends to be a herd with, good water and shelter, and even the bugs have been at historic lows due to our dry weather. I really can't blame Kachina for liking the pasture more than the arena.
|They're a pretty rainbow bunch horses|
|I like to call this photo "Four Big Butts and a Little Ass"|
In the fall the cows will come home for winter and Kachina will have to go back to her pen anyways. I don't want to accelerate that happening, so for now I am enforcing good manners on the ground, like respecting my space, leading at a respectful location, and not biting (she's never come close, but she sometimes thinks about it), but I am trying to ignore the occasional ear pin and not take it too personally.
|This isn't just a blue rectangle, look carefully on the left side|
and you'll see a huge bird of prey (Swainson's Hawk I believe)
that was circling and screeching above the pasture
Side note: yep, our skies are this clear and blue most days
Does this happen to anyone else, where your horse is less glad to see you when they have a primo living situation?