Hi Peggy,This is very timely! I actually just made an email template for myself (a program director) to start informing families as soon as I know their teacher will be absent. It is a brief letter, along the lines of "please let you child know that Teacher X is staying home with his family today, so Teacher Y will be in the classroom. As usual, Teacher W will be there as well!"
I find it helps reduce everyone's stress level, parents included.