Blaundee, you can set up a sprinkler timer on a cheap 9volt $20 timer for any sort of hose system, so electricity is not an issue... I've been doing the same, just wetting down their run mid day so they have some cool dirt to roll around in... Debated on a mister system but I figure these temps are not the norm and usually only here for a few weeks a yr if at all most years... Just had a Wyandotte start limping today, not a heat issue obviously, but worries me nonetheless...
Nice looking birds steen.