The Pou4f3/DTR mouse has become an important mammalian model in which to study inner ear hair cell regeneration. Most HRP consortium labs and many other labs that study potential genes and drugs to induce or facilitate hair cell regeneration rely on this model to behave in a systematic fashion. Unfortunately, on occasion variations of this model have occurred in the colony such that hair cells are preserved after a treatment intended to remove all hair cells. To prevent this from recurring in the HRP’s colony and to replace mice when this occurs elsewhere, the HRP has established a single location where we can be assured of having consistent behavior of the model.