I just recently got two cockatiels. They are both male, and have been cage mates for about 20 years. Their previous owner passed away, and her daughter didn't want them. I don't know much about this type of bird, so any advice would be appreciated. Their names are Martin and Lewis. Lewis has been picking his feathers, and Martin helps him. Now the back of his head /neck is starting to look bald, and his wings and chest are looking rough too. What should I do about this?