I know that all of the curiosities that occassionally (but not always) appear in Sigrun's shop are references mainly to other games. Is the rubber chicken a reference to "King's Quest 7" or "Quest For Glory 4?" Or perhaps some other game with a rubber chicken? From the messages given in the game, I couldn't figure out the exact reference that they were going for

There are rubber chickens in both Quest for Glory 4 and King's Quest 7, and in the absence of a reference to their respective uses, the rubber chicken in Sigrun's shop could be a reference to either, both, or neither of them.