I have had bunches of calls on sick or withering chickens. I too have this
challenge, and I would like to share both operating philosophy and practical

Strong chickens will survive and some breeds still lay well, even in this heat.
The keys to keeping them going without having them share the family room
with you are sanitation and appetite.

Bacteria grows exponentially faster in this heat range
(If you use misters, don't run them to the point of standing water in their run)

Fresh water daily or 2x daily is a must. Inspect the water for being soiled. If
you aren't using a hanging waterer, raise the level of the waterer with bricks so
that the birds can access the water but can't stand in it.

If you are giving them a foot bath, change water frequently.

Wallowing or wallow box is a must - keeps them cleaner & cooler.

Your birds will remain strong and healthy if they keep their appetite up, and
their digestive tract is in good shape to absorb the nutrients in the food they
eat.  The addition of ACV (apple cider vinegar) and or electrolyte to their water
will help their overall health.

ACV (4OZ/gallon of water) increases acidity in their water, suppresses algae
and bacteria in the water, and helps to clean out the digestive tract.

Electrolyte helps water retention and salt balance in their system much like
gatorade. It also contains vitamins which combat different bacteria that may
threaten their immune system.

Contrary to what is widely recommended on different web sites, I do feed my
flock a lot of grain. The difference in my method, is that I finely grind the corn
and oats that add at about a 50% ratio to starter/grower younger pullets, and
layer pellets. The corn provides carbs for energy, and the oats provide fiber for
cleaning their digestive tract as well as protein and other nutrients.
If you are using layer pellets and the birds aren't eating that much of it, try
switching to layer crumbles.

As far as "treats" are concerned, with these brutal temps, if they go after
anything you throw them, throw more to them.

The object of the game is to keep their digestive tract absorbing the nutrients
of anything that you feed them, and keeping those nutrients driving their
immune system to keep them healthy. They have chickens all over the world, in
places even hotter than this, and they thrive when they are healthy.

Hope this helps,
Tips on keeping your flock cool