My Porkchop lost all but one of his tail feathers several months ago when he got spooked and flipped out. One has grown back, directly under the tail feather that did not fall out, but none of his other tail feathers have come back. He had five, previously! He is on a balanced diet with pellets, fresh fruits and vegetables, and nutriberries (at breakfast), so I don't believe it to be a dietary issue. His last vet appointment was just prior to him losing his tail feathers, and he received a gleamingly clean bill of health. Should I be concerned that they are not growing back yet? Is there anything I should do to help?