I dont think it sounds odd, just sounds desperate and I dont blame her..
If I had my own horses that I had to sell one for unknown reasons and I had to decide which one went and neither had done anything wrong to be sold ( like she says in the Ad she would consider full loan.....) then I would take the same route.
Yea I wouldn't pay 4.5k for both of them let alone one of them! lol! Although initially I just found it odd that they'd let "fate" decide which one goes.
Seems to me that they need that amount of money for something and so have decided to put both up for sale in the hope that someone will pay it for one of them