Greetings, I am Dr. Pat. I have worked with birds exclusively for many years. I have a couple of grays myself and have had many African Gray patients.
Can you share any blood work results? What antibiotic, antifungal and what antiinflamatories? Is he on anything for metal toxicity?
There are tests for Borna virus (the presumed cause of PDD) and I would certainly run that test. Also metal toxicity can be evaluated with a blood sample.
I have seen PDD be associated with severe neurological damage including lameness, but generally not with swelling in the legs. And the petechiae-like dots on the face are not seen.
How long has this been going on?
How long have you had him?
Where is he from? Breeder, pet store, private?
Any accidents or trauma?
Interactions with other birds/pets/children/guests?
What is the usual diet? has it changed recently?
Has the bird gotten into anything? Chewed electrical wires?
What is your geographic location and local weather?
IMPORTANT Check the website for the feed you give, there have been many recalls; or check this link:
If this were my patient, and money no object, I would start with complete fecal analysis and direct smear, stained with Sedi-stain and unstained for multiple parasites, fungi, spirals; direct smear stained with Sedi-stain and unstained of the oral cavity; anerobic and aerobic bacterial culture and sensitivity of the feces and choana. Depending on the case I might do a fungal culture. Routine blood work is necessary to rule out other issues including metal levels. There are MANY DNA/RNA tests for bird diseases. Ultrasound is often more informative than radiographs and does not require anesthesia (ask your vet about this option). Generally I start them out on medications as indicated by the tests.
One thing I would mention is that labs often only grow "abnormal" bacteria. I request that they grow ALL bacteria, and have found that many pathogens are overlooked. These include things like C. dificile and MRSA. In a mystery case it is important not to overlook anything. If you are involved with health care, elder care or children care, these are fairly common pathogens in pet of health care workers.
With the GI signs you described I would certainly add anaerobic bacterial culture of crop and feces.
Also I use a lab that only does birds and exotics and they are geared more toward rapid and correct diagnoses.
AAV recommended lab work
Please get back with me and I will try to help.