Feeding 24/7 is also a poor plan for certain breeds - though as you are talking about laying hens, its unlikely you have a bunch of CornishX, which will (if given the chance) eat themselves to severe musculoskeletal problems or even death.
Feeding schedule will vary with your flock needs - most free choice or 24/7 if they have babes in the brooder and even into the grow out pen (unless deliberately restricting intake, as for the CornishX), but use a different feeding method for the main flock.
For instance, i let mine free range by opening the gate while the coffee is brewing, right around dawn typically. Then in the early evening as I put them away, I'll throw some food down and watch their consumption for a bit - it both encourages them to return to the pen on their own, and gives me an idea of how they are faring in their foraging. Occasionally, I offer too much, and they stop eating, go settle down on their roosts - only to be back finishing it in the AM (note this makes a very attractive nuisance for various insects, mice, etc - its not good practice on my part to overfeed - offered out of compulsion for honesty, so you are aware of the potential issues associated)
