Hello, welcome, and I'm very sorry that your bird is going through this. At this point you definitely need to see only a certified avian vet, and absolutely need blood work done, if for no other reason than to see what his white cell count is and to determine how bad the infections are.
He absolutely needs to be on a flat surface and no bars or a regular cage at all. The bars caused him pain, which is why he started chewing his feet again. He's probably got a ton of neuropathic pain in both of his feet and that is why he is chewing them. Tramadol is a synthetic opiate agonist, so if his chewing slowed or stopped while taking the Tramadol then he's in a lot of pain. It's a very good idea that he be on a stronger pain killer that has sedative properties, like Tramadol, because he needs to give his feet time to heal, and any antibiotics, antifungals, steroids, etc. that he's given need time to work fully without him chewing on them. A certified avian vet may try to switch him to Metacam for pain, but I would press the point that Metacam is an NSAID (COX2 Inhibitor) with antiinflammatory properties, but the Tramadol is ideal because it is a much stronger pain reliever, a much stronger sedative, and it successfully stops his pain and is the only med that has successfully stopped his pain, which is evident because he doesn't chew his feet when on it. It's probably best that as far as pain control/sedation/swelling he's on Tramadol combined with either an NSAID or a steroid like Prednisone.
At this point he has necrotic tissue (the black tissue) and most likely that will need at best debrided and at worst cut out/off to prevent it from making his entire foot worse. That tissue is most likely dead, though they should debride it a bit to see if there is healthy tissue/bone underneath, and he'll definitely need another x-ray to look at the bone, not only in the area of the necrotic tissue but at all the bone in both feet to see what the health of the bone is, and to see if infection has spread into the bone.
I would certainly hope at this point the vet would take a culture of both feet and do a Culture and Sensitivity to determine what type of bacteria is causing his infections, and most importantly what antibiotics will kill that bacteria. This is crucial! It really bothers me when vets and doctors just guess what bacteria or fungus is causing an infection and in-turn they guess what antibiotic or antifungal to give the patient...They need to be exact and get the correct meds to clear this up! Colloidal Silver is a great choice that can only help, another topical option is Unpasteurized Honey, it is a natural topical antibiotic and antifungal. But honestly at this point it's very urgent that they properly diagnose the bug or bugs that are causing his infections and get him on the proper antibiotics, antifungals, etc.
Honestly, I believe in your bird's case, in order to completely clear him up, it's crucial for them to #1) Do a culture followed by a Sensitivity test to determine what bugs are causing his infections and get him on the proper meds (along with proper dosages), possibly give him a starter injection of a broad-spectrum antibiotic in the meantime to get him going while waiting for the culture and sensitivity and the blood work, and do an x-ray to determine what parts of his feet/legs are still non-necrotic...#2) Properly and Totally Control His Pain. He will start chewing his feet as soon as he feels pain, he's already proven that, and if he chews them they will never heal. It's already been established that Tramadol works very well for him as an opiate agonist painkiller, so he should be kept on the Tramadol (make sure they give you plenty and the proper dosage that's been working for him), and they should add either an antiinflammatory or a steroid along with the Tramadol to control swelling.
In the meantime you need to keep him out of a regular cage. He needs to be on a completely flat surface that is easily disinfected and that won't hurt his feet. If you aren't already using Hibiclens to clean the container you're keeping him in I would go get some, it is a great wound disinfectant, way better than Betadine, you can clean his feet with a mixture of Hibiclens and water, and make a spray bottle of a mix of Hibiclens and water for easy daily disinfecting of his container, toys, etc. I'd use only paper towels as a substrate at the bottom of his container and change them as soon as they are dirtied.
I wish you the best, please ask the vet every question you have, and demand they properly diagnose his feet.
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