bed down vs sleep in

bed down

verb
  • To lie down to sleep for the night, usually of livestock or machinery. 

  • To put an animal to rest for the night. 

sleep in

verb
  • To sleep late; to go on sleeping past one's customary or planned hour. 

  • Used other than figuratively or idiomatically: see sleep, in. 

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