Nest eggs wet with yolk and white? Egg eater or predator -?

[bloomandbine]

Hi all - we are having what seems to me an unusual situation. I've been collected between 9 and 11 eggs a day from my 12 hens. On the past two days, production is down a few eggs, and those remaining in one nest are wet with egg white and/or yolk. I would assume one of the hens is eating eggs, but there isn't a single piece of shell. Do they eat the shell when hens turn egg eater? Could it be a predator (say a snake?) Or do you think it's a hen laying abnormal eggs? One of my hens was laying incomplete eggs when she first started earlier this summer (soft rumpled shells or no shells) but she appeared to grow out of it and has laid a few dozen lovely solid eggs.

Any thoughts appreciated! I'm working at home today so will spy on the nests periodically in hopes of solving the mystery -

 

[hennible]

My egg eater leaves most of the shells most of the time, but I think they usually eat them. I also have a very old girl with thin shells ( try to pick them up and they sometime break ) those shells and the rest of the egg are usually in the nest box all over the other eggs.
That's my experience any way.