Hey Bruce,
I am in Vegas too, and experienced the heat wave this last weekend myself. Along with several pans of cold water, I put frozen water bottles around the coop and run for the hens to lay next to. Their set up is positioned so that after about 1pm, it is completely engulfed in shade...
I love the idea of electrolyte supplements in their water. I am going to look into that. We live in Las Vegas. I let the girls out sometime between 4 and 5am, and by 7am, we are sometimes well over 100 degrees these days. In addition to several water sources, I keep frozen gallon jugs all around...