your horse is most likely bored. does she get enough turnout time? does she have enough hay when she is stalled?
my gelding started doing this at his previous barn due to not enough turnout time and/or not enough hay being given. i’ve moved him since, and provided him with some fun things in his stall when he is inside like a likit and a jolly ball.
i also have used cribbing eliminator with success. it smells RANCID, but it works 100%. my horse would not chew any of the wood that had been sprayed with it. it’s not as sticky or messy as some of the other no chew sprays. the only downside is the smell (which goes away shortly after application).