I work in a preschool, and I have one co-worker who is consistently late coming in to work, leaving early, calling in "sick," or taking lunches that run long - to give you an idea, she is classified as a full-time employee but has not worked a 40 hour week in 4 or 5 weeks and 3 out of 5 her lunches last week were more than an hour long.
The problem with this is we have a very specific teacher:student ratio that we have to uphold for safety and childcare licensing reasons, meaning that my colleagues and I are consistently having to find ways to cover for this co-worker when she is not in her classroom. I have tried talking to her about this to explain that we're having a hard time finding coverage for her when she's out and it is really stressing all of us out. However, she ended up rolling her eyes at me and walking away, refusing to have a conversation with me about it.
Do I go to my supervisor about it or do I approach her about it again? Do I get a group of my colleagues together to all have a conversation with her about it? I don't want to seem like a whiny co-worker and I certainly don't want to throw her under the bus with the supervisor (I don't want to make a bad situation worse), but it puts us all in a stressful position, and in this industry, puts children at risk by causing us to be understaffed when she is out. How can I handle this situation?