Cousin of the fulvous and black-bellied whistling (tree ) ducks.
You have to assume it to be an escapee first, but they inhabit S America and that is where the fulvous and black-bellieds came from as well. Very interdasting. Should have a band or a footweb clip if its a captive.
The last few years there has been some pretty odd birds coming to and thru south Louisiana. Birds we see everyday now such as roseate spoonbills were not that long ago pretty uncommon in our area. Cattle egrets are actually the very same egrets you see in Africa on Nat Geo walking with the cape buffalo and wildebeast and other plains game. They somehow got here and are right at home following our 'plains game' (heiffers and John Deere tractors

) to kick up bugs
Can you put a point on a map where you saw this please?