To tell which pullet or hen is laying a particular egg:
Pick each one up, and look at her vent (the hole the egg and poop come out of.)
If she's laying, it'll look somewhat moist and stretchy (like an egg could come out of it.)
If she's not laying, the vent will look smaller and puckered.
The first one you look at, you will probably not be sure which way it is.
Once you've looked at both a layer and a not-layer, it will probably be pretty obvious.
Other sure ways to tell:
--sit out there and watch all day
--set up a camera watching the nestboxes, and go grab the egg each time a chicken comes out
--put one hen at a time in a cage alone. If she lays the egg, then you know. If someone else lays the egg, then the one in the cage did not do it.
I've also read of people putting food coloring or lipstick on the hen's vent, and finding colored marks on the egg. Use a different color for each hen, or wait until the color wears off one hen before using it on another. Sounds clever, but I've never personally tried it.
