I'm not getting many eggs here in GA either. I have checked for hidden nests, given them additional water sources, and kept them locked in their coop. I think that heat is to blame here as well. We have been in the 85-90 range for a while, and it is supposed to get up to 95 this week.
It might cool off for a few days at a time, but unfortunately, it doesn't really cool off until Oct or so.
We actually had our first ZERO egg day yesterday...they started laying last Sept...didn't have problems in the winter either...BUT, I just checked the box a few minutes ago and there were 2 eggs and another girl in the nest (We have 6 hens that are of laying age).
Anyway, I guess my reply isn't helpful at all, except to say that you are not alone in your laying issues.