Laying While Roosting at Night?

[Chilebound]

This morning when I let the girls out, I found two eggs under thier roost on the bedding. I am certain that they were'nt there last night when I locked them in. I have 15 mixed (two of these, two of those) six month out pullets, until now they have all layed and used the nest boxes mostly during the late morning or early afternoon. What is going on? is this normal to have an occasional 'roost egg'?

 

[4 luv of eggs]

Someone was asking this very question yesterday. I had a crushed egg on the roost bar yesterday morning myself. I think it does happen once in a while.