cropper vs down feather

cropper

noun
  • A breed of domestic pigeon with large crop. 

  • A person who nurtures and gathers a crop. 

  • A fall, a tumble; a decided failure. 

  • A variety of plant producing a good harvest. 

  • A machine for cropping, as for shearing off bolts or rod iron, or for facing cloth. 

down feather

noun
  • A feather of the down of a bird 

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