The judge in the George Zimmerman trial has agreed to attorneys' request to raise the jury pool from 30 to 40 prosepective jurors before moving on to the next round of questioning.

Judge Debra Nelson also announced Thursday afternoon that the jury will be sequestered during the trial, which she estimated would last only two to four weeks, beginning with opening statements. That's down from previous estimates of four to six weeks.

Lawyers interviewed 10 jurors Thursday and 34 overall. Of those, 25 have been retained for the second round of questioning. Attorneys need to find six jurors and four alternates.

Read a FULL RECAP online from Day 4 of Jury Selection.

During the first four days of jury selection, attorneys have asked potential jurors about the hardships they would face if they were kept away from their families during the trial. Defense attorney Don West explained to one candidate that if picked she would have limited contact with her family, would be monitored by court security outside the courtroom and would have to live in a hotel for the duration.

"You would not be able to participate in day-to-day routine activities," West said. "You will be limited in contact with the outside world."

Zimmerman, a 29-year-old former neighborhood watch volunteer, is pleading not guilty to second-degree murder, claiming he shot unarmed 17-year-old Trayvon Martin last year in self-defense. A 44-day delay in Zimmerman's arrest led to protests around the nation. They questioned whether the Sanford Police Department was investigating the case seriously since Martin was a black teen from the Miami area. Zimmerman identifies himself as Hispanic.

Some potential jurors have been wary of the prospect of being cut off from the world during the trial.

Jury candidate K-80, a middle-aged white woman, described sequestration Thursday as "my biggest fear." Candidates are only referred by their jury numbers in court to protect their identities.

Juror E-81, a middle-aged white woman, said when she saw the word "sequester" on the questionnaire in the jury room, "the walls caved in."

"I want to sleep in my own bed," she said. The potential juror also worried about her safety if picked, saying "I'm going to walk out of here with a bulls-eye on me."

She also appeared to already have made up her mind about the case, decreasing her chances of being picked. Her impression was that Martin's prior use of marijuana and an image of a gun found on his cellphone in photos released by the defense were indications that "he was going down the wrong path." She also said she believed Zimmerman was just "looking after his neighborhood."

"I believe every American has a right to defend himself," said Juror E-81. "I think the more people armed, the better."

Potential juror B-67, a Hispanic female in her 40s, was allowed to leave courtroom without being questioned by defense attorneys after she said being sequestered would be a hardship with her family and school commitments.

Attorneys started off Thursday with a pool of 20 potential jurors who they wanted for a second round of questioning. They needed an additional 10 candidates before they could move past the first round of asking questions about what potential jurors knew about the case from news coverage or social media. But the court announced late Thursday that attorneys requested that that number of jurors needed to move to the second round be raised to 40.

By the end of the court session Thursday, attorneys had interviewed 34 potential witnesses over four days. Ten were questioned Thursday. Five were held over, raising the number of potential candidates eligible second round to 25.

Attorneys need to find six jurors and four alternates. In Florida, 12 jurors are required only for criminal trials involving capital cases, when the death penalty is being considered.