Kentucky's two largest school districts will be closed Thursday after a grassroots network of teachers called for a sickout to protest a bill that would restructure the board that oversees the state's teacher pension system.

Jefferson County Public Schools and Fayette County Public Schools each announced late Wednesday that they did not have enough substitutes to cover the number of teacher absences reported.

Roughly 40 percent of the district's school employees said they would not be showing up to work on Thursday, FCPS said.

KY 120 United, a group that formed during last year's teacher protests, called for the sickout Wednesday evening on social media.

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"Please call in sick tomorrow and text your co-workers to do the same," the group wrote on Facebook.

The group said it is protesting House Bill 525, which would restructure the board for the Kentucky Teachers' Retirement System.

"This bill is as destructive to our pension assets as any bill could be," the post said.

But in a tweet to a Courier Journal reporter, the group's founder, Nema Brewer, implied there are other motivations behind the call for a sickout.

"if u think this is about a pension board - you haven't been paying attention," Brewer said.

Brewer, a public school employee for Fayette County, did not immediately respond Wednesday night to a call seeking further comment.

Earlier Wednesday evening, JCPS Superintendent Marty Pollio and Education Commissioner Wayne Lewis each said they hoped to see schools open on Thursday.

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Brent McKim, president of the Jefferson County teachers union, said his group does not support the call for a sickout.

"We wouldn’t recommend teachers use a sick day for something other than being sick because that could lead to their termination," McKim said. "It’s a serious thing."

If teachers feel strongly about the legislation, they could use a personal day, he said.

But McKim said the union does have concerns about House Bill 525, which is slated to be heard on Thursday by a House committee

McKim said the bill would dilute teacher voice on the state pension board.

The board oversees retirement plans for Kentucky teachers. Seven of its 11 members are elected.

Under current rules, four of the board's elected members are teachers or administrators and are nominated by educators who contribute to the pension system. The board also has one member that is a retired teacher.

The new bill would scrap those spots, as well as two seats for lay-people.

Instead, seven statewide groups would each choose a member, effective July 2019:

Kentucky Education Association

Kentucky Retired Teachers Association

The Kentucky School Boards Association

The Kentucky Association of School Superintendents

The Kentucky Association of Professional Educators

The Kentucky Society of Certified Public Accountants

The Kentucky Bankers Association

Rep. Ken Upchurch, sponsor of House Bill 525, said in a statement late Wednesday night his legislation "seeks to give educators more say in their own retirement."

"It is staggering that people would strike so early in the process and more astonishing that the organization that says they represent teachers’ best interests has called for it," he said.

Upchurch, a Monticello Republican, said he has been working to tweak the bill.

"We have been working for more than a week on a committee substitute that will not only increase the say teachers have — particularly those with (the Jefferson County teachers union) — but also the voice of retired educators," he said. "Despite this, I am hopeful that we can still have a rational conversation on HB 525.”

The Kentucky Education Association, the statewide teachers union, is opposed to the bill and has called it "a retaliatory effort" aimed at educators for earlier protests.

Kentucky was among a handful of states swept by a "red wave" of teacher activism last year.

Blue Grass teachers first staged a massive sickout in March 2018 in response to the late-night passage of a controversial pension reform bill. Altogether, 29 districts shut down for the day as teachers from across the state marched on Frankfort.

Another wave of district closures came in April, after the Kentucky Education Association called for a "day of action" at the Capitol to advocate for education funding in the state budget.

Nationally, teacher protests have continued into 2019, with teachers from Los Angeles to West Virginia already having gone on strike in the new year.

This story is developing and will be updated.

Mandy McLaren: 502-582-4525; mmclaren@courier-journal.com; Twitter: @mandy_mclaren. Support strong local journalism by subscribing today: courier-journal.com/mandym.