Soft- Shelled Egg protruding from Vent and Lethargy

[ChickenPeep]

Hello.
My favorite hen, Ebony started molting a few weeks back and is now in the process of re-growing her feathers. She has been lethargic since she started molting and I'm not sure if it's because molting is so stressful or of she's sick. She hasn't laid an egg since she started molting. Today the was particularly uninterested in foraging. While she was outside today I noticed something white protruding from her vent. It was a soft-shelled eggshell and where were eggwhites and a yolk on the ground. I carefully and slowly eased the eggshell out from her vent and it all came out in one piece.
She is still very lethargic and is currently sleeping on my lap. She has been eating and drinking and getting plenty of protein but I did just remember that I haven't been adding oyster shells to their food.
I'm not sure if this is just a coincidence that it happened to break on the way out or if there's something wrong.

 

[WooingWyandotte]

If I were you, just keep an eye on her for any signs of straining. That could indicate a prolapsed-something, which is definitely a bad thing. Keep us posted.