Lost for ideas - 50 birds and less than 10 eggs a day

[Ljc01]

I think you should leave them locked in and see if your egg production goes up, before you worm them. I hate to medicate my birds if it is not necessary.
Sometime when my hens free range, they lay in other places besides the nesting boxes.

 

[aart]

I would not worm until you have a report on species and counts from a reputable lab.

I think you should leave them locked in and see if your egg production goes up, before you worm them. I hate to medicate my birds if it is not necessary.
Sometime when my hens free range, they lay in other places besides the nesting boxes.

Yes.
Free range birds sometimes need to be 'trained'(or re-trained) to lay in the coop nests, especially new layers. Leaving them locked in the coop for 3-4 days (or longer) can help 'home' them to lay in the coop nests. Fake eggs/golf balls in the nests can help 'show' them were to lay. They can be confined to coop 24/7 for a few days to a week, or confine them at least until mid to late afternoon. You help them create a new habit and they will usually stick with it. ..at least for a good while, then repeat as necessary.

The water situation does not sound good, just a few hours without water can shut them down.

Are there windows in the concrete coop?
Are you providing supplemental light....say are growing shorter quickly.