We are knew to the chicken business, we have a question. I have been putting store bought eggs in my nests hoping to get the chicks to lay eggs in more than one nest. The last 6 eggs I have put out, marked and 2 at a time, have disappeared. Are the chickens eating them or do we have a snake in the coop? We see no signs of cracked shells and no signs of rats. 2 eggs also were in the nest and broken. Two separate occasions. Any suggestions?