why did billy tell landlady about his fillings?

Together, they have a conversation about the guests that were there before, and the woman says some strange things about a Mr. Mulholland, proclaiming, "His skin was so soft". Finally, Billy speaks up, saying that the parrot fooled him from the window, he thought it was alive. The woman says that it is no longer, as well as the dachshund. Billy is worried more than ever, and finally realizes where he saw the names from the guestbook - they mysteriously disappeared, it was in the newspaper.