I know I'm from up North and all but just a few thoughts that might help, as up here, when we have outside (or inside that need it) water lines, going to unheated barns etc, we tend to wrap our lines in poly insulation made for the types of temps they will experience, to try and stave off any freezing. You may want to prep your lines each year by doing this. It may help for a time at least. Obviously, this doesn't insulate your actual tanks though. Others may have better suggestions for that. As far as your water troughs/buckets , have you ever considered building or buying (if finances allow, bc they aren't cheap) solar heated ones? Here are some links for some others have found useful with their livestock. Might save you some time/energy in the long run.
http://ranchtanks.com/
http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm#Animals
https://www.zoro.com/tundra-pipe-ins-poly-2-18-in-id-6-ft-6xe048218/i/G1583023/