Recently I have been noticing fewer eggs than usual in the boxes, and today only 3 out of 7 chickens laid, but when I rolled an egg over there was a hole where the yolk had been sucked out. I was wondering if it might be a predator, pest, or the chickens themselves.
Only once have I ever found a hole in my eggs, and it was done by the chicken herself. Every other time they eat everything, including the shell. What is the largest opening in your coop? If the door is always open it could be anything, but if it's usually shut it may be something smaller like a rat or mouse.