Hi, I have had my cockatiel for a year now after his previous owner moved to a non-pet friendly building. My cockatiel (Joey) is 4 years old and apperentaly has always been a very scared/loud bird. He has never let me touch him and hisses / bites whenever I try to train/tame him or put my hand near him. He has a perfect diet and a big cage with toys and treats/blocks/cuttlefish. He follows me everywhere and loves to cuddle under my chin but is always screaming and is constantly distressed. I don't know how to calm him down / stop him from his aggressive behaviour. I cover him over at night and he has quite long sleeps, I never lock him in his cage except for bedtime so he is always free to explore, I've tried to rearrange his cage, and keep him in a very quiet atmosphere, I've even tried giving him time outs in his cage covered over but I just don't know what to do anymore. I show him so much love and affection but he is really pushing me and I want to make things work. Any suggestions would be greatly appreciated.