Eggs under perches

Up until now all 4 of my hens have laid an egg each every day in the nest boxes, but for the past 3 days there has been an egg laid not in the nest box but under the perch they sleep on.  These are cracked as if they have been dropped from a height, so I deduce that it must have been laid in the night or early morning from the perch.

As all my hens are the same breed I don't know, can only presume the same hen is laying them. 

Any ideas?

Mine do this frequently, the problem is though if one breaks then it starts egg pecking which is the problem I have now, they get a taste for them and start breaking them deliberately.  So rescue the whole ones you see have been laid asap.

Thanks for the replies.  Will see how they go, makes me feel better that no one thinks I'm doing anything wrong!

I would guess its the long nights, Hens learn to hold eggs in as they get better at it, i found mine doing this but they soon learnt to wait a bit longer