Joint Connection Problem

I have a character with a tail and the first bone in the tail, closest to the body, is animated using keyframes. The rest of the bones in the tail doesn’t have any keyframes. What I want to do is to make the other bones be affected by physics using joints while still being connected to the animated bone, so that the tail swings in a natural way without having to animate all of it.

You attach Rigidbody to all tai joints. Mark first joint as Kinematic (i.e. controller from animation or scripts). Attach SpringJoint to others and connect them appropriately.