recent adopted collie

Question
We recently adopted a collie from a rescue. We have had her a little over 2 weeks and she still stays on her bed all the time. We know she spent her life outside  and has had a litter of puppies. She is about 2 years old, now heartworm and tick free. She is not fearful of people, but she is very afraid to be outside and away from her bed. We get her out and she literally runs back home or sometime refuses to go out. I have tried treats. We sit on the floor and pet and scratch her with no response. She is eating, but only when we are not home or in the middle of the night. I feel we are doing everything to make her trust us and feel comfortable. If she moves around the hpuse it is only when we are not home, because she never does when we are around. I am wondering if she could be depressed or if we just haven't given it enough time. It did take her 3 weeks to interact with the other dogs at the shelter. I would hate to medicate her.  I would appreciate any advice you might be able to give me. This is our 4th collie and 3rd rescue and this is a new experience, Thank-you.

Answer
Some dogs have had a horrible life.  What you are doing sounds good to me, keep it up and give her some more time.  She has had 2 years to get into that state.  The rescue may have some good ideas too.  A good one has experience with rehomed dogs and will do all they can to make her placement work.