How is your chicken doing?
Don't know if it will help at all, but I got the report back. I had a previous bird die of Lymphoid leukosis, but the symptoms were not the same. In fact, this recent chicken was not wasting away in the least! However, I have another one that is...and I suspect the same disease.
RESULTS:
Final Diagnosis: Lymphoid leukosis.
Final Comments: Lymphoid leukosis is a common tumour of older chickens. As the tumours progress, the bird is increasingly unable to metabolize nutrients in the feed resulting in an energy deficiency, which presents as immobility and wasting away. Other chickens may succumb to the same disease, but it is not transmissable in the general sense. This is a virus that may exist for their entire life before becoming active and developing tumours.
Hope this helps. Good luck with your bird. Let me know how's she doing.