“Full of wind as a corn-eating horse”

“As full of wind as a corn-eatin’ horse” has been on several Texas slang collections on the internet. The saying has been around since at least 1998.
 
 
Texas Trifles
Friday, March 19, 2004
The Great Texas Buzzard Massacre
I know that some of my readers probably think I am as full of wind as a corn-eating horse, but this tale is all too woefully true.
 
Google Books
Hazard Elimination Inc.
Shaken, But Not Stirred
by Richard Hughes
New York: Xlibris
2002
Pg. 247:
“You’re as full of wind as a corn-eatin horse,” proclaimed Bob, quite proud of his Texas comeback.”
 
Texas Figgers of Speech
AS FULL OF WIND AS A CORN-EATIN’ HORSE.
Rather prone to boasting.