I cannot help you with tracking the Italian origin of the dish, however you can be certain it was not called hasenpfeffer (hase = hare, pfeffer = pepper), in Italy. And while rabbit, or even squirrel

, are accepted as suitable substitues for hare, chicken is not. It is also quite possible that owing to passage of time, regional availability of ingredients, and each home cook's individual interpretation of the dish, that the original Italian version might bear very little resemblence to what is now regarded as a German classic.