I have never used kicking chains.
Does the she only do it in the stall or does she do this when she is turned out also? If it is in the stall does it only happen at feeding time?

The only other things I could suggest is some type of hobbles, like breeding hobbles. They prevent a mare from kicking a stallion and might be a little safer than the chains. Or some other type of hobble system there are so many. If you are around her a lot when she does this I would also suggest a electric collar (Nicer than the cattle prod). A friend of mine used one on a horse that would pace the end of the run on the stall, creating a two foot hole in the ground in a day. With this you could stand out of sight and when the horse began pacing someone would hit the button. It took about a month but the horse quit pacing. Even after removing the collar he never started the pacing again.

Hope this helps.