Lacey worked on Hershel's farm. It is assumed that she was worried about what was happening in the world around them when the reports of the outbreak were coming in. She might have been around when her neighbors were bitten.
Lacey was bitten and died some time after the outbreak. She was killed by walkers who had probably strayed onto Hershel's farm. Before she was reanimated, she was put in the barn on Hershel's farm. She later reanimated as a zombie. This is revealed when Maggie and Glenn argue after Maggie asks why he has to call the zombies "walkers". She also reveals that Lacey, Shawn, her mother, and neighbors are kept in the barn as well. Dale claims he noticed the walkers while on a walk; a lie intended to protect Hershel from the truth of Maggie and Glenn's activities.
Lacey was killed along with all the other walkers in the barn when Shane opened the doors and the group of Atlanta survivors shot everyone that was inside.
Lacey's body is seen at the beginning of the episode on the ground and is later is burned.
This list shows the victims that Lacey has killed:
- Possibly a few zombies
- Zombies (Alive)
Lacey was bitten and infected by the walkers. Over a period of time, she becomes a walker and is taken to the barn.
- Rick's Group (Zombified)
After Shane forces the barn doors open, the walkers (including Lacey) exits the barn and are systematically killed by the survivor group. It is not clear which survivor killed her, it is also unclear which walker she was.