What eggsactly is going on here?!

I left for work very early this morning to wait for a lorry carrying a shepherds hut in a lay-by - but that's another story! Anyway, no one else here remembered to collect the eggs from our girls. I've just gone up to see the girls, who are busy fighting over slugs and baby frogs around (and in!) the pond, and found these 5 egg. Nothing untoward about that you might think. Except we only have 4 girls! So one clever girl, Turk I suspect, has laid 2 eggs today! Clever chooks!