What can I do for Matilda?

I’ve had to bring Matilda – the feral pigeon I treated for string foot several weeks ago – home again today as her foot looked much worse and was hanging by a thread. I have been checking on her over the past few weeks and giving her food but was worried because the foot wasn’t improving. However it didn’t look worse either, until today. Now I’m unsure what to do. If I take her to New Arc they will euthanise her as she will likely lose a foot and they will regard her as disabled. If I take her to the vet for treatment they will also euthanise her so I am unable to get antibiotics or pain relief for her. I understand why wildlife rescues have policies around animals whose disabilities seriously compromise their ability to survive in the wile. But pigeons are very resilient and anyone who has spent any time with urban flocks will know how many of them are missing toes and feet yet still managing to live remarkably well and seemingly without any difficulty. So now I’m stuck with how best…