Some horses never end up anywhere but the bottom of the herd.
If it is too bad then you need to keep her out of situations where she could get hurt, I.e. Too small a pasture for her to keep clear of others, or where she could get hemmed in.
As for foaling and her? She might turn into witch on wheels too. But if you do try for foal she really needs her own paddock.
I've also seen horses that are both fairly low on totem pole, buddy up and move up to 2 or 3 in the herd.
Two that did this, were an 18.2 TB mare, older, and our HQ mare, who was maybe 15 hands, but who was a kicking heifer. She always ended up low with the TB mares, because they called her on her bluff and she lost, much taller than she was.
Legacy, QH and Upturning, TB...got buddied up and what TB could not do because she was too old to battle, QH got settled. Ate out of same bucket, just dumped both feeds in it...and they pretty much did what they wanted too.
Interesting to watch them.
Horses make me a better person.