pigpen vs pigsty

pigpen

noun

  • A pigsty; an enclosure where pigs are kept. 

  • Something extremely dirty or messy. 

  • The pigpen cipher. 

pigsty

noun

  • An enclosure where pigs are kept. 

  • A dirty or very untidy place. 

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