When Amber McCoy called in sick this fall, there wasn’t a substitute teacher who could step into her fourth grade class in Huntington, West Virginia.

Instead, her students at Kellogg Elementary School were taught by a rotating cast of seven staff members, including the assistant principal, who switched off every 45 minutes.

"We are basically relying on every other warm body in our school,” McCoy said. Her current fear is that one day, multiple teachers will be out — with no one to fill in.