Hello, I will be picking up some chicks and will have a 6 hour drive back. I need to set up a mobile brooder with a heat source. I did find one web site that has a "travel cuddler" which is a water bag with cover and a thermostat that will hold heat for 4 hours. Does anyone have any ideas for a heat source I can use to set up a travel brooder? Any suggestions would be greatly appreciated!