Angus Datana caterpillar

When i went to work tonight two young girls found these two Caterpillars just inside the foyer of the school which I thought was strange. Portree high school.

I posted one yesterday I think it was and thought it a one off but tonight when we put the two out the side doors the school was covered in them, they were everywhere. I have never seen so many Caterpillars in one area before especially on a building and no idea why. It looks like an infestation of them if honest.

I will have a look tomorrow when I am back at work and see if they are still there might even take my camera to school as I would never be able to take proper photos with my phone.