You guys are expecting way too much out of a young green baby who has probably hardly ever been handled in her lifetime. You have to start small and work your way up. A lead shank with a chain will NOT solve this. Working with her and training her will not make her worse, it's the only thing that will help. Actually Miss Z is spot on with what will help. She needs to be worked with daily, if not by you then by your dad. She doesn't know what is going on, she has to learn what things are and that they won't hurt her. You need to maybe read Parelli Natural Horsemanship, you can get it from the library and even rent it on DVD/VHS. It will help you learn how to get your horse to trust you and give you "games" to play with her that will help train her and have her trust you so that anything you ask of her later she is willing to accept. Horses don't come knowing everything, just like puppies, they have to learn. Up until now she is learning worse an worse behavior by getting away with acting how she wants to be left alone. Really really look into the Parelli stuff and if that doesn't work there are others, John Lyons, Clinton Anderson, etc. You can read about their techniques and learn how to use them, or your dad can. You can hire a professional trainer but you will do better to learn how to apply it yourself.