and her reaction was almost one of protecting us from him. Just a feeling.....but I am definitely no expert.
An update. I've actually had remarkable results with the ol "pennies in the can" trick. I know, right? It silences both dogs instantly, and we're already to the point where we can lead the new pup right past the male with no psycho responses from either. Fingers crossed, prayers to heaven that it will last!
Your new pup is not protective of you. She is scared and seeks protection from you near you.
The pennies-in-the-can will make her more insecure. It is an "old" technique and should stay in the past.
What she needs is (gentle) leadership, exercise and consistency from you. I would definitely keep her separate from the older dog most of the time to have her bond with you.
At this stage you have to teach her, not correct her. Take her to a good class so you and the pup will build a bond and confidence.
O... and don't lavish her with love just because of her shelter experience. That is history for her and her misery ended when you took her home. Thanks for taking her in.
Suzanne Clothier taught me a very important lesson:
When a new dog comes into your home he has three questions:
1. Who is in charge here?
2. What are the rules?
3. And where do I fit in?
You have to give him/her the answers otherwise he/she will come up with their own.