As the parent of 4 kids who all played together and two of the girls shared a room since toddlerhood I have had many contagious things go through the house and only one or two of the four get it. The same has happened with the daycare. If you aren't closed today while you "think" she has pink eye then not much point in closing tomorrow since by then she has put the germs around if she is going to and she will be on meds by tomorrow with having had at least 2 doses. Things go through groups of kids and it is just a normal fact of life. The closing and sending kids home is more for the appearance of doing something than it actually helping since we all know today and yesterday is when the infection was spreading.