Winterizing Your Water Source- Frost Free Hyrdrant
Pool noodles and duct tape! I would also put a bucket with padding over the hydrants handle to be on the safe side! Always have a small blow torch handy to warm the pipe should it still freeze.
You can also cut a black bucket to fit around the bottom of the hydrant so that the sun will warm the black bucket and give extra heating to the hydrant. I will try and make a diagram to show how to do this when I can find the app that will let me.