The recent picture you posted is noticeably still infected; the area will need to have surgery to promote healing of the tissue and prevent further infection of the surrounding tissue. Looking at your pictures right after surgery it appears you did not go far enough into the tissue to achieve much excavation of the caseous material, and bacterial-filled pus that is likely present inside.
I would personally start re-soaking the foot in an Epsom salts mixture or an antiseptic mixture such as chlorhexidine, or betadine , while soaking massage the area firmly to promote easier excavation of the puss when you do attempt surgery. Once you soaked the mass to the point is readily soft, and tender, you can take a scalpel, and pair of tweezers, and cut around the eschar. Once the eschar has been take out, apply firm pressure in an attempt to squeeze out any caseous material. If none comes out, you may need to dig slightly further into the swelling. If the area hemorrhages, apply firm pressure with a dry towel until the bleeding stops, and continue further.
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After doing the process, gauze, or some sort of padding should be wrapped around the tissue, to promote reinfection, support blood flow, and decrease chances of subsequent trauma to the area until healing has occurred. Antibiotics are indicated in some cases, so if you wish, you could start her on one/ you can get antibiotics online in fish, or bird form. cephalexin, clindamycin, and enrofloxacin would be good choices.
Manuka Honey, Sugardine, and Melafix are some additional products you may find helpful during treatment.
https://glamgouldians.com/product-enrofloxyn.php
https://www.chewy.com/fish-aid-antibiotics-cephalexin/dp/185208
https://www.americanfarriers.com/ar...-mess-that-works-when-treating-wound-injuries
Pododermatitis can be caused by several factors, but a predominant cause seen is poultry, is rough substrate, and perches promoting degradation of the squamous epidermis resulting in flaking, and bacterial invasion into the underlying tissue. Sanding down perches, ensuring their run is easy on their feet can help prevent further problems from occurring.