do all members of the jury have to agree
Hung jury Juries in criminal cases are generally, as a rule, required to reach a unanimous verdict, and juries in civil cases typically have to reach a majority on some level. If a defendant has been found guilty of a capital offense, one that could result in the death penalty if the person is eligible, the opinion of the jury must be unanimous if the defendant is to be sentenced to death. Currently, two states, Oregon and Louisiana, do not require unanimous verdicts in criminal cases. Each requires a 10-2 majority for conviction, except for capital crimes: Oregon requires at least 10 votes out of 12 for felonies, but unanimity for first degree murder, and Louisiana requires all 12.
History of trial by jury in England The English king Æthelred the Unready issued a legal code at Wantage, which states that the twelve leading thegns (minor nobles) of each wapentake (a small district) were required to swear that they would investigate crimes without bias. These 'juries' differed from the present-day kind by being self-informing; instead of getting information through a trial, the jurors were required to investigate the case themselves.[1]