" A falcon tow'ring in her prode of place, was a mousing owl hawk'd at and kill'd... And Duncan's horses... Turn'd wild in nature, broke their stalls flung of contending with contending obedience." ( Act 2, Scene 4) This quote is describing the strange occurances on the night of Duncan's death. It's not normal for a owl to kill a falcon and for horses to become that uncontrollable. The strange animal behaviours are suggesting that fowl play was the cause of Duncan's untimely death.