battue vs mass murder

battue

noun
  • A hunt performed in this manner. 

  • A form of hunting in which game is forced into the open by the beating of sticks on bushes, etc. 

mass murder

noun
  • The killing of a large number of people over a short period of time. 

How often have the words battue and mass murder occurred in a corpus of books? (source: Google Ngram Viewer )