Hi Bill,
A lot of times Petsmart features kittens from shelters and these kittens come from all kinds of different backgrounds–sometimes from feral moms. But that’s okay, because these kittens get adopted and have a chance for wonderful lives in loving homes. Thank you for adopting!
I think that with lots of time and patience, Gertie will be fine. She is only 6 weeks old, so she has a lifetime of wonderfulness ahead of her as opposed to where and how she learned her fearful attitude. Just let her get used to the sounds of your home, the appliances (dishwasher, washer, dryer, etc.) no loud noises, and if you have a dog try and make sure it’s not barking at her. If you have her in one room, you can sit down with a book and read aloud so she gets used to the sound of your voice. Play soothing music, offer her some treats, wand toys, things that will teach her that only good things come from her humans. Eventually, she won’t remember her fear and she won’t be hiding. You can also block off areas (under beds and furniture) so that she has no place to hide and has to be out in the open.