I am a new chicken farmer and I only have a few chickens. My chickens just started to lay eggs and, since they hadnt before, i missed the first two. I put a green mark on each one so i wouldnt mistake them for fresh eggs. I put the eggs into the nest box and the chickens kept laying so i left the old eggs in there for about a month. I went out to the coop yesterday to get the eggs and one of the old eggs was gone. It had to be frozen because the other one was like a rock. I still dont know what got the egg. Do chickens eat eggs, if they dont, what could have taken it?