All dogs have some type of prey drive, it goes back to their wild roots. Some breeds will have a higher drive than others, for instance, dachshunds are a hunting breed and therefore should have a high drive. BUT that is not always the case, there are some doxies who could care less that a squirrel just ran across the top of its fence. My boy has a decent drive, he won't tunnel during an earth dog test, but let him track something down and he's a happy boy.
The breeders are mentioning it because they want you to be aware of it before you take a pup home and then call them back in a panic wondering why the pup acts the way it does. Most Hunting (Hounds), Sporting (Retrievers, Pointers, Setters & Spaniels) Working breeds (Huskies, Malamutes) and Herding breeds (Collies, Shepherds) tend to have high prey drives as do some terrier breeds. The best way for you to tell if the breed you're looking at is going to have a high drive is to look at what it was originally bred to do. (Even mutts will display high drives, depending on their cross)
Good luck in search for a new family member!