We've gotten a strange egg like this twice now from our Barred Rock hen. The picture has one of her regular eggs on the right. When broken open, the weird eggs have a normal yolk and very watery egg white. Any idea what may cause this? Our other 2 hens have never had this problem. They are young, hatched in September, just started laying in February. Their diet is layer pellets with the occasional bit of fruit or veggie scraps and a small handful of bird seed to peck at every day.