due order vs pecking order

due order

pecking order

noun
  • The natural hierarchy of social status and dominance occurring in a group of birds. 

  • The usually informal hierarchy of authority or command, often partial or approximate, as determined by the especially natural propensity for domination of different members of a specific group over each other, such as older brothers and sisters over their younger siblings. 

How often have the words due order and pecking order occurred in a corpus of books? (source: Google Ngram Viewer )