molting feathers

Hi all, My one of the cockatiel facing feather loss last few weeks. Especially in back side and tail. We shifted to new home last few months back. I dont know is the new place not comfort to him or lack of air circulation or any disease.. Please advice how to prevent feather loss asap.

I have a cockatiel that is about 6 years old. It has been with me for about 1 1/2 years. The previous owner gave it to me. It cannot fly. It occasionally tries to fly but the 4 longest feathers on each wing are missing. The bird does not like hands at all so I cannot really look at the wings...