I agree .. that looks like a possible soft shell which has broken. I have a hen who lays a couple of soft shells when she is moulting and on two occasions they have broken inside her.
I have found with her that she usually manages to deposit the remainder of the soft shell when relaxed on the roost overnight.
As you are doing, keep an eye on her just in case infection sets in.
I have found with her that she usually manages to deposit the remainder of the soft shell when relaxed on the roost overnight.
As you are doing, keep an eye on her just in case infection sets in.