Overall, assess their body language. A hot chicken stands with its wings away from their body (not opened up, just lifted off their body), and they pant with mouth open. If they are doing neither of these things, they are not too hot.
They have shade and some air flow, so you have done the two biggest things for them. The other one is cool water!
My full grown chickens have days where they are hot and panting, even in the shade. So, cool/cold hose water with ice cubes added. Then in the later afternoon when the entire coop and run are shaded, I give them wet feed with ice cubes so as they melt it adds water to the feed - my chickens like soupy feed. I do this to get them to eat and drink at same time. In really hot weather, they start to lay less, partly bc they may not be drinking enough water.
Chicks are smaller, so they have less body mass than an adult and more skin surface area to body mass, so should be able to keep cool a bit better than an adult chicken. You may have lighter feathered breeds, as well, and that will help ty to stay cooler with less feathers. For example a Cochin is very heavily feathered, but a Leghorn is much more lightly feathered.
