Anon has kept chickens off and on muh whole life. I've seen eggs laid with no shell and only the thin lining that normally lines the shell. Doesn't happen often but it does happen.
Anon couldn't do the blood spot ones and got tired of being chased by roosters so last batch I had, made sure there was no rooster. They don't lay as well, but no blood spots in the yolks and no mean rooster.
Anon's grandma had a flock of chickens. They were white "leggerns."
They had no pen or house and she never fed them except for the food scrapes that were raked off the plates out the back door, which they had to get to before the cats under the house did, or there were none. They roosted in the sweet gum behind her house at night, and she knew where they laid their eggs on the edge of the woods, so she would go gather them everyday. If she ever lost any chickens, I never knew it. If animals are left to be their natural selves, they are pretty self-sufficient.