This is for humans but I am convinced that one of the main culprits of all parrot woes is diet, which is why I advocate fresh food (alive with enzymes, beneficial bacteria and antioxidants) instead of pellets, dehydrated or freeze-dried food, etc.
Gut feelings: the future of psychiatry may be inside your stomach | The Verge
Gut feelings: the future of psychiatry may be inside your stomach | The Verge