brood vs chew over

brood

verb
  • (typically with about or over) To dwell upon moodily and at length, mainly alone. 

  • To be bred. 

  • To keep an egg warm to make it hatch. 

  • To protect (something that is gradually maturing); to foster. 

adj
  • Kept or reared for breeding. 

noun
  • Heavy waste in tin and copper ores. 

  • Parentage. 

  • The children in one family; offspring. 

  • The young of any egg-laying creature, especially if produced at the same time. 

  • The eggs and larvae of social insects such as bees, ants and some wasps, especially when gathered together in special brood chambers or combs within the colony. 

  • The young of certain animals, especially a group of young birds or fowl hatched at one time by the same mother. 

  • That which is bred or produced; breed; species. 

chew over

verb
  • To think deeply about; to ponder or mull over. 

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