During really hot days and weeks I put ice cubes in the water bowls. They really appreciate it and will come running when I add ice. Also if I water down the area where they are hanging out in the shade or leave the hose on just a drip really seems to keep them from panting.
They like standing in this shallow bowl with a little water, it's actually a ceramic plate for under a pot. The ceramic doesn't seem to absorb much heat so the water is always relatively cool. Every now and then one of the hens will stand in a taller water bowl, but not very often.
