For those of you who have never had four 14-year-old girls sleeping round your house before, here's an example of what a room looks like after they (plus your daughter) have slept in it:
It's as if some kind of bomb has gone off.
The other thing to note is that they all bring their favourite soft toy with them, without which they are unable to sleep. Given that they don't tend to do much sleeping anyway, this seems rather pointless; still, they do it. Most of these toys are so in need of a wash that they probably have things living in them, but they can't be put anywhere near water because it's only the dirt that's holding them together.
Oh well, it could have been worse. They could have been boys.