Hi, I'd like to help you with your question.
Children who have witnessed domestic abuse react in different ways. At the age your daughter is, you would be able to talk with her about how she feels and what she wants. I would sit with her and ask her how she feels about moving to a new home. Explain that everything would be new and different and help her to understand how moving works. Some children would see leaving their homes as traumatic and upsetting. Other children see it as an adventure.
Also, you need to determine if your child would feel just as unsafe in a new home as she does now in her current home. Does she feel the danger comes from her father alone, or does being in the home traumatize her with reminders? In other words, would moving improve the chance she feels less threatened by her father? Would she feel safer?
Has your child been in therapy? She would benefit from talking with someone to help her work out her feelings about what she saw. It would also give you a chance to talk with the therapist about a possible move and get her insights into the impact a move would have on your daughter.
I hope this has helped,