Long before the rest of the country knows about certain products, companies will choose small test markets to see if they're worth releasing on a national scale.
I've actually lived in one of these places and while we were never explicitly told why we were so lucky, we think we might have figured it out. The area is not interested in trying new things to an honestly pretty grumpy extent, so if a new product is a hit there, it'll probably be a hit everywhere.
So if there's a reason besides local grumpiness why Hershey's decided to show something delicious to an undisclosed town in Wisconsin before the rest of us can even see it, I'm sure I don't know it.