From what I have seen rescues get these pups several ways. One of them is by them being shut down, as well as basically like a whole sale when they have too many pups that havent sold ect. If the mill is expecting a large load of fresh litters they will get ride of them at a discounted price.
It would be interesting to find out more about this process and how rescues and rescuing works though. I hope someone here will have more knowledge than me on the subject.
