Shade is a must! I use the frozen 2-liters also. I wash them with anti-bacterial dishsoap and then place back in freezer...reduce, reuse, recycle!
The frozen 2-liters seem to help them the most, they perch on them during the heat. I place them in the coop where their fan is with the fan blowing down on the 2-liters. They have adjusted to the heat and no longer pant unless it gets over 100, then I break out the 2-liters. I spray their run down also, keeps the dirt cool. Try not to mess with them too much during the heat of the day, keep it cool and quiet.

