I think the reason many people here are reluctant to pass judgement is because there’s a big piece of the puzzle missing as to why the owner changed her mind. Are the horses less sound than she let on? Did she have questions about the new home, based on previous bad experiences with the person who said she was wiling to take the horses, experiences that she mulled over and ultimately swayed her mind in a different direction? We don’t know the full history or every conversation between these two women, even if they were friends.
There are 100% crazy people in this world who feel they’re the only ones who can care for their animals–hell, any animals–properly, and I’m always horrified to hear when people demand their relatives euthanize young, healthy animals in their wills. But without the owner’s side of the story, we don’t know for certain that’s the case. In this version of events she’s completely irrational, going from welcoming a new home for her horses to locking and barring the gate. That might be true, especially if she’s going through the grief of losing a farm because of finances, but again, we really don’t know if she’s one of those nutty people for sure, until we hear her version of the events.
I’m not really sure “inconvenience” is the right word to describe the rationale behind her actions, though. Sure the most convenient thing would have been to let the animals go for free and move on with her life. She may be selfish, irrational, spiteful, who knows, but she made a great deal of effort to end the arrangement for some reason.
Is it absolutely certain that the animals were put down? Or might she have found another home?