There are at least four labs in Texas, maybe one of them could do a necropsy for you?
https://www.aphis.usda.gov/animal_health/nahln/downloads/all_nahln_lab_list.pdf
-Kathy
And check here if you wan to find a vet to treat her:
http://www.aav.org/search/custom.asp?id=1803
http://www.majesticwaterfowl.org/vetfinder.htm
-Kathy