Just to make sure I understand the numbers:
You have 43 chickens.
You are getting about 3 eggs each day, but you think 4 chickens are actually taking turns doing the laying.
So that would mean you have 39 chickens that are not laying.
Is that right?
If you have 43 chickens, and you are giving 2 cups of scratch each day, that works out to less than 1 tablespoon of scratch per chicken per day, which should not be a problem.
If you actually have 4 chickens, and the "43" is a typo, then 2 cups of scratch would be way too much. 1/4 cup of total treats per day would be much more reasonable for 4 chickens.
I have four Barred rocks that I am getting 3 or more eggs every day from. They are roughly 27 weeks old. I have been using supplemental light for the coop. I typically turn it on at 7am, and leave it on until 8:30pm to 9pm. I also have been loading them up with meal worms and other proteins to stay warm as they can. I also added a few extra roosts, and some other random things to climb on like ladders to keep them from boredom.