Don't give up on her yet....But you will have to retrain BOTH dogs....Which won't be easy...To start you have to let them know that YOU are the #1 dog and that aggressive behavior between them won't be tolerated...Small things that you do send signals to the dogs so start sending the signal "Enough is Enough"...I work with bird dogs mostly, on obedience/respect issues for their owners....When a dog comes to me it is "Expected" to play by my rules...not the rules that he/she has been previously taught, Those previous rules are sometimes why they come to me....There is no fighting, sometimes a little posture growling but never to injure each other, The new dog just gets it after a few days...And it isn't easy my 2 house bird dogs,GSP's, are both female and both "think" they are the boss...Except they never "test me" because they know...Left unsaid I never Beat/whip/starve/even yell at a dog...YOU ARE WASTING YOUR TIME if your training methods include those things...Teach them to respect you, never to go through a door before you,allow you to pick up their food bowl while they are eating,make them wait for you before they do something...once a dog realizes you are the boss, he won't keep asking you (or testing you) because he knows the answer to the question....Teach your 2 dominant females that they are welcome to feel however they want but draw the line at them being physical with each other in a hurtful way....Who cares if they growl at each other...walk over to them, and grab one of them by the ear...Tell them to stop...then grab the other one and do the same thing...Don't hurt them just grab their ear to get their attention....Sorry about the long post...I hate to see dogs leave a good home and go "somewhere else".....JMO