brood sow vs piggy

brood sow

noun
  • A female pig kept for breeding. 

  • A woman raising children. 

piggy

noun
  • A pig (the animal). 

  • A toe. 

  • A pig, a greedy person. 

  • A member of the police. 

  • A guinea pig. 

adj
  • slovenly, dirty 

  • greedy 

How often have the words brood sow and piggy occurred in a corpus of books? (source: Google Ngram Viewer )