In The Crucible, Cheever says that cows are running freely in the streets. Why are they roaming?

Cheever is really describing the chaos that has taken over Salem with the witch trials.  The entire community is in an uproar and fearful of those accused of witchcraft.  People are coming out to the trials on a daily basis leaving their farms unattended.  The atmosphere of the community has declined and paranoid accusations are “running freely” like the cows.  The Salem and the Puritan religious structure is starting to breakdown with what they think is rampant witchcraft in the community.  The free roaming cows and vacant fields show how the fanaticism of witch craft has caused people to neglect their daily lives.  The town’s people are more interested in the theatrics of the trial than their own well-being. 

Lives have been turned upside down with the accusations brought about by Abigail and the girls.  The Puritan community is sinking into pandemonium echoed by the cows running the streets of Salem.