Fans inside houses unless you have large windows that lots of wind blow through at animal level. Summer is the one time that direct wind on the chickens is something they like.
Frozen water bottles. We use nipple waterers made out of 5 gal buckets - frozen water bottle in there to keep the water cool enough to drink. If I ever use a "regular" waterer, I freeze some water in the dome and then fill the rest of it with water before hanging it. When it is over 100* or if one of the birds is looking too stressed, then frozen bottles go out in the runs with them and in the coop. I also dump out the water every day into the run - the birds like to lay in the water on the ground.
Shallow containers for the chickens to wade in when it is hot - usually buy cheap kitty litter pans.
Frozen fruit, especially things like watermelon slices help cool them down when they stand/sit/lay on them and they get more hydration from eating the frozen melon as it thaws.
Some people use misters in the runs.
I would recommend going to a higher protein feed during the heat if you feed regular chicken feed routinely after they are grown. Since they are eating less when it is hot, their protein intake can go way down, so they will get a little more protein in each bite if you increase the protein in their feed.