What is this? Pic included

[sunnie7]

Pretty sure I’ve read about this but went to collect eggs and it was almost dark at first I think there’s a little snake in my nesting box! Then got my flashlight and this is what it was, there was a yolk too. What is it and what causes it? I do have a few that are just starting to lay….

 

[MysteryChicken]

Pretty sure I’ve read about this but went to collect eggs and it was almost dark at first I think there’s a little snake in my nesting box! Then got my flashlight and this is what it was, there was a yolk too. What is it and what causes it? I do have a few that are just starting to lay….View attachment 3016421

Shell-less egg with a tail.