I do several things to keep my birds cool. They free range on my fenced acre. I do not have a pen, just a large coop. It does get hot where I'm at in summer, in the 90s and sometimes around 100. They like to hang out under big blue spruce trees I have around the property. When it gets 85 or more, I run two mister hoses through the trees branches. They love it under there, and it cools it down by almost 20 degrees.
Another thing I do is feed them really cold melon, either cantaloupe or their favorite, watermelon. I also freeze 2 liter plastic pop bottles with the top narrow part cut off. Be sure to use the straight sided ones, or you won't be able to get the giant ice cube out of the ones that are shaped like an hourglass. Put those ice chunks in the waterers, and it keeps the water cold. The ice floats, so doesn't interfere with the flow.
Lots of shade, misters, cold treats, and ice. I have not lost a chicken to heat yet.
Another thing I do is feed them really cold melon, either cantaloupe or their favorite, watermelon. I also freeze 2 liter plastic pop bottles with the top narrow part cut off. Be sure to use the straight sided ones, or you won't be able to get the giant ice cube out of the ones that are shaped like an hourglass. Put those ice chunks in the waterers, and it keeps the water cold. The ice floats, so doesn't interfere with the flow.
Lots of shade, misters, cold treats, and ice. I have not lost a chicken to heat yet.