a cribber will always crib, I'm sorry to say, as long as they have something to crib on. There are ways to stop them from cribbing though.
Putting the hot wire (or whatever is the "right term" for it) and fence your app in with that. Removing any wood, metal, plastic, from their pasture.
Putting hot wire just on the top of the fence won't work because they will crib on the bottom of it...any thing they can get their teeth on they will crib. hehe.
There was a study that showed that sweet feed makes a horse want to crib more so if your feeding the horse sweet feed, I'd probably take that off her diet.
Also cribbing (from what I've heard) is hereditaty...they actually inheirit it from a parent or some relative. (but I could be wrong on that not sure how accurate it is)