I keep layer feed available to my chickens 24/7. I've noticed that I usually have to refill their 30 lb. feeder every other day (to fill it 3/4 full). There are times when I expect their consumption of the feed to increase - during the wintertime when there's less for them to forage for & if they are stuck in their coop for long periods of time during stormy weather, etc.).
If I notice a sudden decrease in the amount of layer feed they are eating, I still keep filling the feeder, but cut back on their treats. The treats they can live without. Their layer feed they need.