The Hatfield's and the McCoy's in the Bible?

No, the tales of the Hatfield's and the McCoy's are not in the Bible.

But there are tales that mimic their feuds.

Genesis Chapter 34 starts out with the rape of Dinah, the daughter of Jacob and Leah, by a guy named Shechem, who was the head of that region of land in Canaan.  He then fell in love with her and went to Jacob to ask for her hand in marriage.  Jacob informed him that he would have to be circumcised in order for him to allow it, so Shechem did as ordered.

Three days after the circumcision, Jacob's two sons, Simeon and Levi, went into the city where Shechem and his family lived, and killed them all.  They then looted the town of all its livestock, women, and children.

Jacob was furious about this, for he didn't have an army to fight against anyone who vowed revenge for Shechem's death.  Jacob then prayed for God for protection.  God sent Jacob to Bethel, where he then named Jacob Israel and gave him the same promises as he had Abraham and Isaac, that vast nations will be descendants from you.