I do the mud puddle thing and it works great. I also had no luck with frozen water bottles... they looked at them like they were plague carrying varmits. I also refill the water bowls 2-3 times a day depending on the heat. we've been near 100 lately and they seem to enjoy the puddles the best. They dig down and make themselves a nice little bowl in the dirt under the grapevine shade and hang out. I like the frozen leftover idea. May have to try that out.