This paper explores the character of medical experimentation through the long history of one seemingly bizarre remedy for plague buboes. Appearing often and in various versions between 1348 and the eighteenth century, the basic treatment involves placing a live chicken on a poisonous swelling, such as a plague bubo. This project explores physicians’ ideas on how the remedy worked, and more importantly, how the remedy changed over time from its roots in Avicenna’s Canon through the arrival of the “Black Death” and up to its full blossoming in early modern times. The project uncovers a long history of experimentation in the many extant versions of the remedy, drawing on the writings of physicians Jacme d’Agramont, Johannes Jacobi, Antonio Guarineri, Niccolo Bertucci, Caspar Kegler, Johann Reusch, and Ernst Reuchlin, among others. Focusing on the vernacular pamphlet literature of early modern German physicians, I also investigate physicians’ personal observations on the remedy’s efficacy as well as the minor changes that they recommend. Through such cases, I describe medieval and early modern medical experimentation amid changing relationships between theory and practice, ancient authority and personal experience.