Snakes are very capable creatures. And they are smarter than we give them credit for. See if this will help you get a good night's sleep tonight:
https://www.google.com/search?q=sna...0j69i57j0l4.5163j0j7&sourceid=chrome&ie=UTF-8
As for disappearing ceramic eggs: I have 2 and have actually marked them so I can tell them from the real eggs. They are very convincing in shape, wt, color, size. My ceramic eggs often move about in the coop. They travel from one nest box to an other. At least one of my hens will move a ceramic egg so she can have it in her favorite nest.
Eggs returning to the nest with tooth marks? Creepy! I've found that my dog is a white bellied egg sucker. I caught her raiding the egg basket that I had set on the deck. Before I realized what she was doing, she had stolen 3 eggs and carried them down onto the lawn for her "picnic". I bet the ceramic egg thief was a dog.