As far as misters go... you'd have to check at the store near you, of course, but at the Home Depot we frequent, they have a kit for sale for $20. It has the 12' starter set plus a 10' extension set. They're easy to install and you can add additional extensions up to 50' total length. We bought one today and had it hooked up in the coop and running in 10 minutes. They don't typically run this deal, and the starter set itself is $17, so it's not a bad way to get your chickens a misting system quickly if your local HD has it. We're looking at 106 or higher this week in Tucson, so we figured it'd be a good idea to get something going now.
Installation consists of the following: 1. Connect to hose. 2. Route misting system (it's a flexible plastic line) and attach, using either the nail u-clips or you can find some zip ties. 3. Turn on water and adjust the aim on the nozzles. Ta-da, you've got a misting system.