I have 4 Barred Rocks, 3 White Rocks, and 2 Reds. The Barred are molting. I don't know who lays which eggs but have found the remains of an egg or two on several occasions but no shell fragments. Yesterday I got an egg with an extremely soft shell--actually more like a water balloon that an egg--with what resembled an umbilical cord attached. I have no rooster. Is this normal? Could they be laying eggs with little or no shell as they emerge from molt?
I think you hit the nail on the head. A soft or even shell-less egg can occur during the molt. Here's an awesome article that discusses various egg abnormalities. #10 in the list mentions what you describe. https://www.backyardchickens.com/a/common-egg-quality-problems Good luck to you!
How old are your birds? There's no doubt that funky eggs.... thin/soft shells, really odd one...can happen just before and just after molting. Just like when they first start to lay as pullets. The 'remains' you found is also pretty common...a thin or soft shelled egg is easily broken then fair game for eating IMO, the shell or membrane gets eaten up also and you often find just a wet spot.
