Friends and searchers took to the route at dusk Thursday, following the path on which Shunick set out in the early hours of Saturday morning. FBI, U.S. Marshals and local police are involved in the search that they are treating as a missing-person case, but have not ruled out foul play.
Shunick, 22, a senior anthropology major at the University of Louisiana at Lafayette, left friend Brettly Wilson's house on her bike just before 2 a.m. Saturday after a night out, and hasn't been heard from since.
"I asked her to be safe ... I saw her get to the driveway and that was the last time I saw her," Wilson said.
Friends and family held a candle light vigil Tuesday night, and announced a reward of $20,000 for tips leading to her whereabouts. Searches by K-9 units, police and volunteers have turned up no hints of what happened, but her family remains hopeful.
"I think she's OK, I think she's alive. I think she's out there," Mickey's sister, Charlene, told ABC affiliate KATC-TV in Lafayette, La.
The FBI, state and local police, and nearly a thousand volunteers are searching this morning, but have found no trace of the young woman. Friends say she wasn't drinking, and that Shunick was an avid cyclist, so riding her bike at that hour was not unusual.
Shunick's older sister says she never would have left on her own, and that Saturday was her brother's graduation. Monday was Mickey's own 22nd birthday, and the two had big plans.
"She's my mini-me. She's one of my best friends and I just miss her and I want to know what's going on," sister Charlie Shunick said through tears.
For her father, not knowing is the hardest part.
"If she has been taken by somebody, where is she? What are they doing to her? It's better being around people like over here. It's tougher when you're alone at night," Tom Shunick told ABC News.
Her family says they can't think of any reason anybody might want to harm Shunick, and her father said although he's grateful for the search efforts, he wishes the search had started earlier.
"None of the video cameras got checked over the weekend because the managers weren't in and waited two days to check the video cameras," he told Lafayette newspaper The Advertiser. "If somebody has abducted her and taken her on the interstate highway or something, they got a two-day head start."
Mickey Shunick always carried mace when she rode her bike, her family says, adding that they will keep searching, no matter how long it takes.
"We're going to see her soon, we're going to get her home and this is going to be over soon," friend Wilson said.
Shunick's family is offering a $25,000 reward for any information in the case. They say that they hope everyone is on the lookout for her, including those in states that border Louisiana.
The family plans to send out a robo-call today to the entire parish -- which consists of hundreds of thousands of people in the region -- hoping that someone knows where Mickey is.
Shunick is 5-foot-1 and 115 pounds. She was last seen wearing a pastel multi-colored striped shirt, light-wash skinny jeans and gray shoes.