Good Morning and welcome to Just answer. I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
I am so sorry to hear about Lilly's condition.
This is common in reescue dogs because you donot know how Lily was treated before you got her. Here are tips to help her past this:
. Purchase a DAP Collar (Dog Appeasement Pheromone) at the pet store. This is a canine pheromone that acts as a calming agent and will decrease anxiety. Rescue Remedy is also helpful.
2. Carry a coke can with pennies in it and when you see this aggression starting, shake the can loudly and say a strong NO!
3. have your vet examine Lily checking for a medical cause such as hormonal issues or metabolic problems that could cause this. If this is ruled out, ask your vet for an anti anxiety medication such as Clomicalm or Reconcile that will decrease the anxiety that is causing this.
5. Consider contacting a veterinary behaviorist that can help Lily past this. This LINK will find one near you.
6. Take Bella back to a good obedience class so you will have better control over her.
This LINK will have more tips.
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please Reply so I can clarify for you
Sincerely, Dr. Loretta