Wolpertingers are something like a folk myth in Bavaria (south Germany). They don't really exist but are combined of various parts of hunted animals. The German text you've quoted is about ordering any of the specimen they are offering and about prices, not about the myth.
From wikipedia:
The Wolpertinger (also called "Wolperdinger") is a mythical animal supposedly living in the alpine forests of Bavaria in Germany. It has body parts of various animals — generally wings, antlers and fangs, all attached to the body of a small mammal. The most widespread description is that of a horned rabbit or horned squirrel. It is similar to the Elwedritsche of the Palatinate region, which resembles a chicken-like creature with antlers, and to the American invention of the jackalope.
Stuffed Wolpertingers, composed of parts of real stuffed animals, are often displayed or sold as tourist souvenirs in their "native regions". Each village has its own set of tales about sightings of the Wolpertinger in the nearby countryside.
