I Have 4 chickens and only get 2 eggs a day. How can you tell which of the chickens is laying?

If your chickens are young and have not yet come into lay then you can look at their vent ( opening in their bum) and see if it is tight and puckered or wider and loose. Chicken that are laying have more open vents. Chickens only lay two eggs every three days, one about every 25 to 26 hours in high production. You almost have to catch the hen on the nest and cackling to prove the egg was from that one.