Head tilting with a sick animal is often also accompanied by the animal walking in circles. They hide their illnesses so long, that they really dig in and took root before you notice them. When the circling starts, you're in trouble. It's causing imbalance issues and it's affecting their neurological system. It's very, very hard to save a chin that has reached that point. Rats you can do it with, but they frequently retain the head tilt even after they are cured. I only know of one chin that was saved after progressing to the point of walking in circles. I know I myself had a girl who did it and, despite my best efforts, it was a losing battle.