Ok sorry for all the questions but what I was trying to get at was his age...usually when they are more quiet and they attempt to bite but really aren't hurting you when they do, it can mean they are very young but thats not always a for sure. As for the bald spots...they do normally have a bald spot under their crest and they will have a natural baldspot on their neck over their jugular but the scratching thing isn't normal. He may have picked up something when he was flying free. It may also be a female so consider that. Males do tend to be better talkers but if its a young bird, you may not know that for a while. I would have your vet do a health check on him to make sure everything seems ok with him. You can feed him whatever you eat but do avoid things like onions and avocado's. Feeding him a varied diet or a pelleted diet is best because with an all seed diet, they tend to pick out what they like and thats usually the seeds that have no nutritional value like sunflower seeds. With a Be sure that he isn't near a draft. Things like fireplaces can also cause respiratory issues. Also be sure to be very careful when using teflon coated cookware because if you burn something in a teflon coated pan, the fumes can be toxic to any birds.