Joshua and Jacob Rips began the role of Zack Brady but were quickly switched and started playing Jt Brady. They boys both shared the cover of Soap Opera Digest on June 13 2000. before they even shot the birth scene's. The boys were quickly replaced in July because they looked too healthy to play Jt, Who suffered from Fetal Alcohol Syndrome. But the boys returned December 20, 2000 to play Jt.
Lauren and Alyssa Libby played the birth scene for Jt Brady. And switched over to play Zack. The girls began the same day the Rips twins did, June of 2000 and held the role till April 20, 2001. They were recasted because the people at Days believed they were looking too much like girls.
Max and Sam christy took over the role of Zack in April 2001. They were casted because the Libby twins were looking too much like girls and they needed little boys in the role. Before doing days the boys were seen on General Hospital as Sonny's young son in his dream. The boys only lasted 4 months in the role of Zack before they were replaced.
Spencer, Garrett and Mitchell Grey took over the role of Zack on august 31 2001. The boys weren't new to days. They were back up for the Christy twins, and filled in the June 13 2001 episode when the Christy's were out sick. Mitchell is fraternal whereas Spencer and Garrett are identical but he was used as a fill in when necessary. The boys held the role for 4 years till Zack was tragically killed when he was struck by a car. While still on day's the boys filmed a pilot of Big Love, and can now be seen as Raymond on Big Love.Memorable Quotes

Four Christmases
Marley & me
Bedtime Stories
Home Movie
Ghost Whisperer
Big Love
Lost S05
11:11
Land of the Lost
Imagine That
Astro Boy
A Christmas Carol
Labor Pains
Love at First Hiccup
Opposite Day
Sweet Flame
Malevolence: Bereavemeny
Southern Baptist Sissies
S Darko
Twixter
Meteor: Path of destruction
Perfect 10
The Spy Next Door
Jack and the Beanstalk
Winged Creatures
Mississippi Damned
Pheobe in Wonderland
Burning Palms
FootSteps
The Trouble with Cali
Magic
Out Numbered
The Kings of Appletown
The Oaks