Sadie - 4mo german shepard (Phoenix)

Hi I have a 4month old female purebred german Shepard puppy.
She does well with other dogs and kids.
Reason we have to get rid of her is my old dog is not getting along with her.
He’s a little chihuahua, and he snaps at her.
Her name is Sadie, i believe you can train a new name with her.
I will reduce the rehoming fee I paid by half.
So a rehoming fee of $300