Weird egg

[ChickenTenderz]

I just collected this egg with no shell and what looks like an umbilical cord, is my hen ok? We are in the process of switching back to layer feed since we have added 3 new chicks to our flock. They are getting 50/50 chickstarter & layer feed now and are allowed to free range most days.
The hen I saw standing over this egg is a 3 year old Rhode Island Red. I think she had just laid it (9:30 pm) when I opened the coop door to make sure everyone had come to roost for the night.

 

[Wyorp Rock]

It's a soft shelled egg with a tail.

If it's a one time thing, then mark it up as a glitch. If she lays another, then I'd get extra Calcium into her for a week. 1 Calcium Citrate+D3 tablet directly into the beak once daily.

Soft shelled eggs can be the result in changes of flock dynamics (new birds), change in feed, change in weather...many things.