There can be plenty of problems. Has this guy tried frozen thawed? I had a pastel het clown who would flee from a frozen rat... I pulled it out, placed a live one in, and it struck and constricted, then consumed as if it hadn't seen a rodent in months...

They can be quite picky. Getting them to eat what you want them to eat can be quite frustrating. I'd say keep your corn, tell him to sell or re-home his ball python, and get a BP who is already taking f/t .