Question: What is Mr. Clucks?
Mr. Clucks was first introduced in Episode 1x18, Numbers.
Answer: Mr. Clucks was the restaurant where Hurley worked. Their tag line was "Have a Cluckety-Cluck-Cluck Day!"
Hurley's boss there was Randy, who was also Locke's boss at the box company.
Hurley quit after winning the lottery and then later bought the restaurant, but it was hit by a meteorite.
