One of my chickens just died from the heat

I am feeling really down about it and upset. I don't know where else to talk about it. I'm at work right now trying to not cry while facing the public. My husband and daughter called to tell me about it and my poor little toddler daughter was so distraught.

Ugh... My chickens are more of pets to me. I only had six. Five now.

Any tips for keeping chickens cooler in a heatwave/summer in general? They have a fan, two big water containers and multiple shady spots, but its 105+ every day lately.