My area just went through a spell of hot humid weather(no breeze) 3 box fans running with cardboard lining the walls of the coop.
Chickens started panting. One by one I soaked them in a rubber tub full of water to cool them off. They didn't fuss, and just stood in the tub until they cooled off.
This sounds very familiar, however, I try to discourage the chickens to Not go in the woods since the local wildlife I have matches yours.
I box trap any unwanted critters, luring them in to the trap with part of a banana. Raccoons seem to love bananas.
No ravens here... but plenty of "birds...
The waterer most likely has a galvanized (toxic) coating to make it last longer. If it's rusty on the inside, it is probably not safe for your chickens to drink from.
Most car washes have a hard time getting rid of the empty chemical barrels. The barrels will most likely need to be thoroughly power washed inside with hot water.
I've been playing around with putting together a rain barrel system, with 6 55 gallon drums (all daisy chained) in my basement. Only difference is my water is coming from under ground (pumped by a sump pump). No concerns about any contaminants from roof debris.
2 barrels are full, and working...