@timi Like I said before, egg whites ( nearly pure protein) are very good for a bird occasionally. Egg yolks are nor all that good for them. Yolks are full of saturated fats, one of the major causes of heart problems and atherosclerosis in birds.
PDD is a fatal disease that can be controlled - to an extent.
You don't know if your bird has PDD or not and will not know without extensive testing. Be aware that many vets throw PDD out to a client as the possible diagnosis because they are at a loss. It does little to no harm to treat a bird as if he has PDD, since mostly treatment is supportive. Celebrex or Onsior are the chosen anti-inflammatories used in the treatment Of PDD.
Please read the following article (it is recent since written in 2020) attempt to understand and them come back if you have additional questions or need explanation.
PDD is an inflammatory disease affecting the gastrointestinal and neurological systems in a variety of bird species
veterinarypartner.vin.com