You can give them frozen fruit or veggies. Mine love cucumber. Make sure they have a mud wallow in one corner of the run, and fans on. We lost a couple of pullets yesterday, so now there's a block of ice in front of the fan and electrolytes in the water. In a pinch, you can use pedialyte, or get chicken electrolytes. And a bit of molasses in the water, if they are really stressed. We moved all the pullets in with the hens, because then hens are under a pecan tree. We're in high gear trying to keep them cool here; the heat's going up and staying up with no relief in sight. Oh, and give them change-outs of cool water when you can, and ice in their water. Good luck.