Mare w/ history goes nuts when stablemate leaves
Hi. New here. I recently started working at a private stable. There is a mare there that if we get along in the saddle well, will be my horse. I've spent the last week letting her get used to me around her, grooming her etc. She's gradually calmed down more each day, nickers to me, and today was turning her neck to rub against me as I was rubbing her down. She also set her head over my shoulder and closed her eyes. Always has an ear toward me. Seems good to me, but I never trained in nht, so not sure. The mare has had nht training though for a few months. I always go w/ my gut and am gentle yet firm with any horse I work with.
Her history is one of neglect at one owner, who sent her to a retirement farm for half a year. She is 20. For the past 2 years she's been living at the place I'm now working, had her health restored, but the owner is finding it hard to find a suitable mount for her. Other than her doing some nht, the trainers she had out bullied the mare, and the one rider she had riding her, she said tried to bully her as well. The mare is very flighty under saddle I'm told. She's a Thoroughbred.
The biggest issue, and I think helps feed the flightiness, is that when her stable mate- another mare, is out of sight, she goes nuts. Starts to circle and call for her. The owner said going to a show, or trying to ride them separate is a cause of stress, because the mare is so upset. She also mentioned that because she's not being worked, she's starting to chew on things out of boredom.
I have absolutely no idea what to do. I'd like to go on to groundwork w/ the mare, but if she's so distracted when the other mare is gone, I have no idea what to do. The mares go way back as well. They were both owned by the same owner over 10 years ago, split up for years, then lived next door to each other and would call to each other. Now they are together again. The current owner is thinking of selling her unless she can find a rider that the mare will bond with-thinking this will improve things. She would rather the mare stay where she is, instead of worrying where she may end up if she does sell her.