There aren't enough subs everywhere. At our school we have 1 great sub for the small school and juvie. That's not enough. Everyone else either doesn't want to work here, because it's hard, or admin doesn't like them, because they're not good or have gotten other jobs and left. Currently, if I was to call out, I'd need to let my admin know, so she can make arrangements, instead of just let the absence go into the system and end up with someone who can't handle it.
I also believe this about my district; my school just does not want to pay for subs. Why pay for subs when you can get your teachers to cover classes for free?
Wow, admin steps in and takes classes? A-mazing. At my school, our kids get split up. I cannot tell you the number of times I am at school until late at night planning for a sub and then my principal forgets to call in a sub or a sub doesn't show...or better yet, my P will tell me the day before that I am out the next day.... My principal is VERY out of touch with what happens in a typical classroom
In middle and high school, when students switch classrooms and subjects all day, splitting classes is not really an option.