Well, it sounds like your hens are returning to normal. Unless she lays some more odd eggs, I bet that her egg-laying system was just maturing.
In answer to your other question, hens don't usually lay more than one egg at a time, and most sources say that they can't. Sometimes they do, though...
It appears that your pullet is having some problems with her reproductive tract. More than one yolk was probably released from the ovary at a time, causing both to travel down the oviduct and have some albumen (white) added to them. If a shell had been added, this might have resulted in a...