Extra Egg!!

Hello Folks,
I am totally baffled this morning as there were 4 eggs to be collected (from 3 hens) instead of the usual 3.  I had no idea a hen could lay more than one egg a day? When my husband went out early to open them up and clean out the house there were none (as usual) then within 3 hours I went out and found the 4 eggs.  What is happening?  Has anyone else had this happen?   

Since Christmas i have had 7 eggs from 6 birds, twice
My hens are really laying well at the moment (37 eggs this week)

Thanks, it is nice to know I don't a peculiar girl!  Mine are laying really well and seem to love running about in the snow here in Suffolk.  Hattie, our Black Pearl has taken to kick boxing our little conifers to make the snow fall!! She thinks it is a great game.

That is sooo cute, any chance of any piccies?