Hens stopping or reducing laying is a very common topic on here. Some things to look for.
Are they molting? Different things can cause a molt, even out of season. Are you seeing feathers floating around? If you are seeing many feathers we can discuss this in detail.
A very common reason we think they are not laying is that they hide a nest on you. Some of them can be really sneaky about hiding a nest in the coop or run, even if they don't free range.
Is something getting the eggs? Many egg-eaters will leave clues, broken eggshells or a wet spot. Snakes, canines, and humans do not. A snake will eat a few eggs and disappear for two or three days while it digests them, then come back for more. If it is an everyday shortage it is not a snake.
A fox or coyote would probably be more interested in your hens but a dog might leave the chickens alone and eat eggs. Does a dog have access?
A human does not have to be a stranger. In some cases it has been someone playing a practical joke or someone living there taking the eggs.
Sometimes if they are stressed they can take a break. Predator attacks (real or perceived), a change in pecking order, going without water for a couple of days, or changing their housing or nests can cause a disruption in laying. Extreme heat or cold can also cause a change in laying.
I don't know where you are but with the heat some of us are seeing that could be the culprit.
So what can you do? If you can lock them in the coop only or coop and run you may keep them from a hidden nest or lock out an egg-eating predator. It sounds like you started free ranging after the problem hit so this may not be very helpful. You can discretely mark an egg ort two and leave down there. If they disappear you know something is getting your eggs. Other than that, the only thing I know is to wait it out.
Good luck! This can be frustrating.