The puppy may be thankful that it is a journey of freedom and that he will never see this chain again.
There is not a day when a neglected dog is removed from his miserable life and taken to a place where he feels safe. Dogs are very smart and can know when a change is going to change. In the video below, the battered puppy has just been taken out of her life in a series, and she reacts in the best way.
A grateful dog may feel that this is his freedom, thanking the savior by burying his face in his arm and then gently putting his paw in his hand. The savior is so moved by everything that she cannot resist the tears. Everything melts the heart to see. We are very happy that this dog is safe and healthy for the rest of her life.
h/t to PawMyGosh