Green duck egg

Last month I reported that one, possibly two, of our younger ducks, hatched in the summer, had started laying. It seems we now have a third. Today a slightly green egg was in the duck run when I arrived on the allotment this morning. I put it next to one of the other duck eggs laid recently for the above photo as the green colouring is very pale. It is likely that it is the young aylesbury that laid it.