Not enough information available to be anywhere near sure, but I'll try a few possible causes. How long has this been going on, a few days or a few weeks?
They may be molting. Have you been providing extra light then changed that? Maybe they have been stressed by something? Have they run out of water for a time? Many different things can cause a molt and sometimes it is not your entire flock that molts.
Are they hiding a nest on you? This is a real common cause for a drop in egg production. A real common cause.
Is something getting the eggs? It could be the chickens themselves. They usually leave evidence but not always. There are many predators that could be eating eggs. Some leave evidence and some don't. With it being a fairly regular amount each day, my list of suspicious characters drops a bit. A snake usually does not eat that many and usually does not show up every day. Rats, possums, coons, foxes, skunks, and many others are usually not that regular either, especially if you do not leave the eggs in the coop overnight, but any of these could show up in daylight too.
If it is something regularly getting the eggs, my first thoughts would be your pet dog or a human, but it is hard to really nail it down.
Have you changed the pecking order, either by adding or taking away any chickens? Maybe moved them to new quarters? Changed what they eat? Has the weather changed dramatically? Some flocks cut back laying in hot or cold weather. Any of these can cause a drop in egg production. Chickens usually don't like change.
Sometimes just seeing a predator close by can cause them to stress and quit laying for a while.
Do they need worming? Have you checked them for mites or lice?
A drop in egg production is not all that unusual. Sometimes they just seem to take a few days off. But a regular drop like this over a period of time does need investigating. Good luck! This is not always an easy one to solve.