Just visited with an old friend, my sister-in-law's horse.  It's been 8 years since that horse taught me how to ride.  Seems she's gotten a bit cantakerous lately.  I used to get on her bareback and she'd watch out for me.  She'd shift her weight or stop till I can catch my balance.

Now I'm told she behaves only when my SiL wears spurs and carries a whip.  Barn sour, I suppose.  Boy, do I wish she was her young self again.  She sure made me feel very safe on her back.  With my ever creaky joints,  I'd much prefer her undivided attention but without the whips and spurs.  The devices, in my mind, violates the inital level of trust between us.

 I wonder how she would be if you were to ride her again, without a whip or spurs?  It could be she's barn sour, it could be an age thing, or it could just be the way she's reacting to the way your SIL rides. It would be interesting to see how she reacted if you got on her back.

Whips and spurs are aids, not means of punishing a horse. They're not meant for making a horse behave. Or for making the horse forward. They are not for MAKING the horse do anything; they're for delicate REQUESTS. If the mare cannot be ridden without spurs or whips, she is not trained properly. Period. If your SIL relies on spurs and whips to get anything from the mare she is not riding the mare well, or even RIDING the mare at all. She's just sitting on her.

SiL hasn't ridden her much and is thinking of letting us have her.  When we visited, I took her out of her stall for some grazing and grooming.  It was nice to get to visit after a long time not seeing. 

There is something about meeting up with the first horse that took care of you and did not dump you.  I have always held up every other horse we've had to her.

I think it would be a great idea if she came back to you.  I'm sure with some regular attention and work, she'll come back around and be a pleasure to ride again.

Another thing to keep in mind is the mare's age. If the mare won't move without punishment she may be in pain. Check the fit of her saddle and tack: a saddle that fit when the mare was younger may not fit now. Even if the tack fits, it may be pain somewhere else. She might be just trying to tell her rider that she can't do what she's being asked for b/c it hurts. Rather than resorting to whips or spurs to get her to do what is asked, the FIRST thing to check is existence of pain.