It is quite normal for her to be acting this way. When someone who is used to getting what they want is not able to convince you to give it to them, they get angry and lash out. She is very angry with you and thinks that if she threatens you or scares you enough that once again, she will get what she wants. Quite likely, she's not used to people standing up to her. She is in fact "bullying you" She will use what ever scare tactics she thinks will get her what she wants. You have done nothing wrong. Keep all the correspondence and log all the phone calls and visits. Call the local law officials and if it goes on too far you will have a basis to get a restraining order against her. Once this RO is logged against her, she will be more angry and will try to threaten you again. If for some strange reason it went to court (I don't believe for half a second that it would) you have all the paperwork and even the local cops would have it on record that you have filed complaints on this person.
Now you not only have to stand up for your rights and freedoms but also for the animals rights. You will be fine. It may not be easy but I'm confident that it will work out. She could just be blowing a lot of steam from her butt.