Thanks
@FrostRanger. That was my original thought but neighbor was evasive about means to the end and it just wasn't a discussion we were able to have. Moreover, the state vet was a little skeptical about what might be discovered if shipping the body across the state. I was pretty much done emotionally, by this point, so since vet never called, I went for what seemed most efficacious, as poor bird was still hanging on but in really bad shape. My priority changed to simply getting her culled--as quickly, as humanely as possible.
Also, I thought state vet at least gave a reasonable hypothesis about what was wrong that seemed to fit the situation w/Chicago. Given that she was already old for her breed and I had an idea she might have had parathyroid cancer, I decided to let it go. That is, it seems it likely was nothing that could have been prevented and the treatments or care I attempted were reasonable under the circumstances but not sufficient to address the underlying condition(s).
I weighed what might be learned against sticky situation with neighbor (trying to influence method of culling) and additional stress to me in attempting to ship the corpse. Hope that makes sense.