farm cat vs feral cat

farm cat

noun
  • A domestic cat, usually of a mixed breed, that lives primarily outdoors, in a feral or semiferal condition on agricultural properties. 

feral cat

noun
  • A domestic cat that has returned to or was born in a living situation without human care. 

How often have the words farm cat and feral cat occurred in a corpus of books? (source: Google Ngram Viewer )