It really isn't too important, unless you are truly only wanting to keep and feed those that are laying.
The best way to keep records of day to day egg laying would be through the use of trap nests. It is a nest box with a specially designed front that keeps the hen inside the box until you release her. These can be a little bit more costly and time consuming, because you have to either buy or make the trap-nests and you have to make sure to do multiple trips out to the coop to make sure the hens aren't locked up all day. There would have to be enough for every hen(or all but one), because once a hen goes inside the door comes down and it makes the next hen have find another box.
If you just have a flock for eggs and pets, it is not important to know which ones aren't laying eggs. But if you want to save on feed, by caring only for those that are 'pulling their weight', then you will have to either separate every hen or use the trap nests. Egg-laying records are also important if you are trying to breed high quality show birds, and want to be very very picky about keeping track of which hen laid what egg.
-Kim