What is happening to my chickens?

This is the 3rd time this happens. We get chickens -- they lay for a few days and then NOT A SINGLE EGG!

Do I have some weird plant growing in my yard? Do they start eating them? Is this a diet change?

First eggs they layed in the boxes. Then, all over the yard. Then, nothing.

Please help me brainstorm this! 🙏🙏

First, are you sure the coop is fully secure and there's not chance that some sort of vermin isn't disturbing the birds in their nest boxes?

Second, a picture of the boxes would help. Many boxes are deep and dark enough to really be a "preferred location."

Third, are you sure there are no mites in the boxes. Some mites can hibernate for years and then come out and bother the birds as soon as they smell them. Do you dust the boxes with Diatomaceous earth, as it discourages mites.

Once, you've confirmed the above 3, I would then see what happens if you keep the birds locked in for a week to see if they get the idea that nest boxes are the right spot. I have had Ravens fly right into an open coop to steal eggs, I've heard of both squirrels and snakes stealing eggs.

This thread might give you some ideas of nest boxes that chickens like:
https://permies.com/t/171763/Nesting-Boxes-Hens-Big-Put

Can you give a bit more information on when you typically get your chickens and when you start getting eggs from them?

Also, you may already be aware of the natural autumn slow-down or stop in laying, but just in case.....   -->  https://www.chickencoopcompany.com/a/blog/understanding-how-chickens-lay-eggs-in-fall?srsltid=AU7gw4UBRjmodVQwwNTvNTQ-LMwEjWIHIpi2fJT7xaxas-as5ca8KOlT