Its been in the mid to high 90's for weeks here in Northeast Florida. The humidity is the devil, but now that there are wildfires in Georgia, we are getting smoke and heavy ash all day long.
My chickens have a kiddie pool with holes in it to keep the water hose trickling in it to a shallow level. My birds love cooling off in it.
Because my flock is 100% contained in a completely covered/shaded pen(the sun and natural light come through the side, but don't actually beat down on the birds), we had to figure out a way to keep a breeze going with the ventilation in tact. My husband also took fans and mounted them at either end of the pen on the ceiling so there's a cross-breeze.
I've been providing ice bottles like those previously mentioned above. I have also given them water with electrolytes as a supplement to keep them from being dehydrated/heat-stressed.
I'm sorry for those of you who have lost your feathered family members. It's important to be vigilant always---severe weather/sickness/predators, etc. As we all know, caring for any pet is a full time labor of love.
I wish the best to you all.