I have 3 ISA Browns. Seems like once every week or so I find a huge egg. Size comparison....When I shut the lid on one of the 1/2 dozen egg cartons, it will hardly close. And these eggs have two yolks. Is this common? I don't mind cause they are great tasting. But just curious if something is wrong? The egg is odd-looking, like it has a slight ripple in the shell. Thanks for your opinions.