Easy way to see which year layers are laying, every other year when you switch out layers, get all brown layers, then all white layers and so on. :p
Or you could probe them every morning for a week. Never done it but know someone who has.
Now that I am dropping below 14 hour/ day I have decided add lights to the coop. I would not want to do a timer because the sun up sun down time is always changing. I did not want to run a light censored light with and extension cord because of the hassle and I do not want the light on whenever...