A wave of teacher absences described by an activist as "rolling strikes" shut down more than half of Detroit's 100 public schools Monday, keeping thousands of students at home as a so-called sick-out entered a second week.

A handful of high schools were forced to close last week due to teachers calling in sick. But the action Monday was more dramatic as more teachers stayed home.

The Detroit district with 46,000 students has been in turmoil, struggling with millions of dollars in debt, poor morale among staff and families that have other school choices for their kids.

Ivy Bailey, interim president of the Detroit Federation of Teachers, displayed photos of mold in schools.

"This is why those sick-outs happened," she told reporters, adding that classes have too many students and rodents are plentiful.

Gov. Rick Snyder, a Republican, wants to pay off the debt and spin off a new district, but he lacks support so far in the Legislature. There are no ongoing negotiations between teachers and schools, which are run by a Snyder appointee, emergency manager Darnell Earley.

"We understand and share their frustration," Earley said in a statement, referring to teachers.

But the absences make it "more challenging" to reach a political solution with state lawmakers in the Capitol, he said.

A teacher and former union president, Steve Conn, said the shutdowns were "great." He warned the district Sunday that parents needed to be notified about the "rolling strikes."

Click for more from Fox 2.