Maybe you can try to desensitize her to yelling by speaking loudly to her that she's a good girl, and over a period of time raising your voice around her when you're praising her. She might begin to associate loudness with excitement and fun . Yes, it could be her previous home, or she could just be a very sensitive and shy dog... Gonzo was extremely scared when anyone would raise their hand up anywhere near him, he would shrink down and look really pitiful. I *know* his breeder was very rough with him when he was young, and probably hit him atleast a few times before we got him when he was 8 months. Now, after a lot of patience and desensitizing, whenever anyone raises their hand he jumps around and gets excited because he thinks youre about to throw a ball...