What is their history of egg laying? How many eggs were you getting? How old are they? Did they molt over winter?
Heat can slow their egg laying but probably not this much. I think something else could be going on. I'll go through my usual list.
Are they molting? I know, this time of year where you are this isn't very likely, but are you seeing a bunch of feathers flying around.
A typical reason egg production drops is that they are hiding a nest. Do yours free range? Even if they don't they can be really good at hiding a nest from you. People often find a nest in the coop but not in the nest full of a lot of eggs.
Most things that eat eggs leave some type of trace behind. That might be egg shells or a damp spot. I'm not sure what country you are in, but in the US the only critters likely to leave no trace are snakes, canines, and humans. A snake will eat eggs and then disappear while it digest them, coming back in a few days for more. Since it is consistent every day, it is not a snake.
Many canines like a fox or coyote would probably be more interested in your chickens than the eggs, so probably not them. But a dog could easily leave your chickens alone and eat eggs.
A human doesn't necessarily mean a thief or a stranger. Some people have pulled practical jokes like this.
So what can you do? If they free range maybe leave them locked in the coop/run and see if any eggs start showing up. That would mean they were hiding a nest from you or you locked out an egg eater. Or you can mark a real egg and leave it down there. If it disappears something is getting them.
Good luck. This kind of stuff can be frustrating.
