I'm in Houston, so I hear ya' on the heat. It's miserable here lately - the birds are suffering from it.
Depending on the age of the birds, here are some things to do.
First, I find a place in the yard where the birds hang out that stays shaded all day long. Those places tend to stay cooler. If the birds don't hang out there, tempt them to by throwing scratch there daily.
When I do my early chores, I wet the leaves over that area, wet the ground a bit. If the birds don't go there, I'll put a pan with scratch out under the tree- just a bit. Put a water container there so they are drawn to there to drink. Put multiple water stations out during the summer. They don't have to be fancy - can even be just pans of water. You can put a frozen gallon of water in the pan to cool it.
Wetting the leaves in the cooler area makes an 'air conditioned' area, especially if the leaves drape to the ground. I actually leave some plants as bushes in my barnyard so that birds can hide from the heat there.
For smaller waterers, you can also freeze small drinking water bottles of water and put those in the waterer (cap off - so that when they melt they replace the displaced water with more melting water.
Our flock has a very small wading pool, like you can get for pets at
Petsmart (the bigger ones for kids are too deep). They're pretty cheap. My turkeys love to stand in that water, which I put in the shade. You can put pans out and see if your hens will stand in it. Mine love puddles in the summer. Put those under the shadier areas.
For electrolytes, I never use electrolytes from packages in the summer full strength because birds will overdose on them by drinking a lot. Instead, use it 1/4th strength or less. Or you can use Organic apple cider vinegar in their (non-metal) waterers. That'll keep the water from getting scummy in our heat, gives them a natural electrolyte that they don't overdose on at the rate of 1/2 ounce ACV per 1 gallon of water. Use organic - it's more expensive, but you don't use much, and it contains other nutrients that will help your Texas chickens combat bacterial issues that we have with our water in the summer because organic has living bacteria in it. Also organic is made by bacteria, not through chemical fermenation. It's a vitamin D supplement for their laying, electrolytes for the heat, probiotics to ward off summer stress related issues and gut problems, and has enzymes so they digest their food better. It's worth every cent.
Be sure to take care of yourself, too. Hydrate yourself 10 minutes before going out to do your chores. When you're misting the leaves and ground, mist yourself a little too.
It's brutal out there, isn't it?
If they're babies, I'd use frozen water jugs and a box fan blowing that onto the babies.
So are you getting a possible drought in your part of Texas? The lack of rain here is making it cooler, but miserable for the horses, etc.