I live in high desert in So Cal - 120F is possible. No matter where I live, when it gets HOT out, I always offer chickens plenty of shade & water. I like to add vitamin/electrolye powder to the water, once a week or more often. I also try to leave the chickens alone during the hottest part of the day, to keep from stressing them. Fresh fruits and veggies are good, too. Depending on the housing for your chickens, you might want to use a fan to keep the air moving. Hens tend to lay less when weather is very hot, so keeping them as cool as possible will help them keep laying for you.
Make sure your coop has good air flow at night in hot weather, while keeping chickens safe. If the coop is too hot in the evening, they won't want to go in. Plenty of roosting space is important. In cold months the chickens will want to roost close together to keep warm. In hot weather they will want to spread out, so you need twice the roosting area in hot months as cold.
Water MUST be kept clean in the heat. Warm weather breeds bacteria in water fast. I've also frozen chunks of ice in big yogurt type containers, and added them to a shaded water bowl mid-day, to help keep chickies cool.
If free ranging, chickens will seek out the coolest part of your property. You may not want them wandering like that, but they will. If the safest area provides food, water, and the best shelter from the elements, that's where they will be. Most rural areas have plenty of chicken predators, from Coyotes, foxes & dogs to weasels, raccoons, opossums and skunks. Most of these predators will be resting in the heat of the day, but when hungry, you can't be sure they won't be active mid day, especially if they have hungry young to feed. No matter how you keep chickens, if they aren't safe from predators 24/7, you won't have chickens for long.
If your chicks are from a local hatchery, chances are the breeding adults were well acclimated to your type of weather and they can pass this to their chicks genetically. If your chicks came from a very different climate, or are breeds that don't do well in extreme heat, you will need to take extra care to make sure they are comfortable.