This is really getting to me..(very long be prepared to do some reading)?

She's obviously one of those people that is in the horse business for the money and not the love. If anything I would call her out on it. It's awful to hear something like that. I would be devasted giving away so many horses. I get attached far too quickly. I know some horses have to be sold but she sells them like candy it sounds. She also is awful for lying about the horse and I honestly hope she gets called out on it because that's a pisser. My horses are my world and I wouldn't trade them for anything. Hell, someone just dropped off a mare in my pasture without warning and I am considering keeping her. I don't know how you can stop this because she has her mind set on it. But your parents should have control of the horse trailer and make sure to clean out everything that your horses touch before they do if she lets one of the selling horses use it. I would talk to your parents and bring up all the points you did and see what they say and good luck. I hope you get some justice.