Should school lunches be free for all? A pandemic experiment.

Long involved in fighting childhood hunger, public schools are providing free meals this year – regardless of family income. The unplanned experiment offers clues about what works. Third in a series about hunger in America.

It’s 5 p.m. on a Tuesday, and Cathy McNair and a few student volunteers are ready to go. They’ve wheeled out a couple dozen boxes of pre-packaged meals – some donated and some from the school’s food services provider – to the Finneytown Secondary Campus parking lot in suburban Cincinnati.

High school and middle school...