Let me share some part of the book, and I would appreciate if you give me the answer to my question.
There were undoubtedly many of these children and grandchildren, as hillbillies tended to have much higher birthrates than the native population.
In short, my grandparents' experience was extremely common. Significant parts of an entire region picked up shop and moved north. Need more proof? Hop on an northbound highway in Kentucky or Tenessee the day after Thanksgiving or Christmas, and virtually every license plate you see comes from Ohio, Indiana, or Michigan--cars full of hillbilly transplants returning home for the holidays.
In Korean version, it is translated into like "Significant parts of an entire region moved north along plants(or factories)" or "Significant parts of an entire region moved north, looking for plants(or factories)."
I don't understand what "pick up" means here, what's more I don't get the hang of "shop" here. Does it any mean factories or plants? It is even used without an article, really confusing.