Kristi, maybe you could call the shelter and explain that she can get into rescue if she's returned again and asked to be contacted if she is? This poor soul is emotionally damaged enough from being a mill dog, but being passed from home to home at this stage in her life will just reinforce her fear and insecurity and make her less and less able to be rehabiltated and adopted.
Mill dogs need a very special foster situation to prepare them (and their adoptive family) for their forever home. As Mary Palmer said, they need another dog in the house for security and as a positive role model. They also need very limited exposure to strangers so a "come look at my new dog" situation would be a disaster.
Here is some information from the Puppy Mill Rescue group on what someone adopting a mill dog should expect:
Before you confirm your interest in adoption I would like to tell you a little bit about what it’s like to live with a puppy mill dog. I know we tend to want to save them all, but PLEASE, PLEASE DO NOT ACT ON THE SPUR OF THE MOMENT, "I want a doggie" syndrome. Think it though as this is a LIFETIME decision -- much the same has having children would be.
These dogs are not housebroken - they will pee in your house... please make sure your entire family is in 100% agreement with bringing another dog into your home - and that they all also understand the many problems that can occur.
If you have allergies, then a dog may not be the right choice for your household.They can be hard to potty train. Some are NEVER truly trained. It maybe very trying to deal with some of their issues, like poop eating, excessive fears, or an excessively needy dog.
They tend to be frightened of sudden moves, loud noises, and sometimes even the touch of a hand. Some dogs will never be a normal dog due the neglect and treatment they received in the mill. These dogs also tend to run or bolt if given any opportunity to do so and can be very hard to catch because they are afraid.
It takes time to build the trust that the mills stripped from the dogs during the time they were in the mill. They can go from being very scared to being totally dependent upon you, in such a short time.
They may attach themselves to one person in the home and become their protector and not want to allow anyone near that person.
They may not want to be separated from you. They can become very stressed if they are boarded. They remember their life in the mill and they feel as though they have been placed right back into that situation when they are boarded and put in a cage, groomer cages can be a problem too.
You have to be willing to take time out of your current lifestyle to help this poor unfortunate soul who depends solely on you.
These dogs have many needs and they have been through heck living in a small cage, not getting enough to eat, not knowing understanding, love, patience, or the gentle touch of a hand. Some have spent their entire lives living in a cage with their feet never touching the ground.
They do not know what the feel of grass is beneath their feet. They have never been walked on a leash so you will have to teach them just as if they were a puppy.
These dogs generally require ongoing vet expenses.
They tend to require dentals more frequently due to their years of neglect of dental care. They may require some, if not all, of their teeth to be removed if they are older. They may develop joint problems, after they are adopted, that were not known prior to adoptions because of their years of inactivity confined in cages.
It may take several months to get the puppy mill smell out of the dog. No matter how many times that you wash the dog, the smell may come back. This is embedded deep into the pores of the dogs and it will take time and good food and care in order to rid the dog of this smell.
These dogs do not really know how to act like a dog, this is something that they will learn over time with much patience and understanding, and the help of your other dog in the house.
Caring, patience, no preconceived notions of the perfect dog, or the perfect dog in a week or a month, dealing with the dog's issues, and being willing to wait till the dog is ready to be touched, pooping or peeing on the floor, hoarding toys or food, growling, or barking.
Some dogs may also be somewhat food aggressive. Any and all of this might be in your future with your new puppy mill dog. These dogs are not "perfect", but they can learn and they do deserve to be loved.
So if you are not up to a great challenge, then a puppy mill dog is not the dog for you. All this is very important to understand as we are trying to find the best home possible for these animals that have been treated so badly in their lives until they came into our care.