I do have a couple questions.
Are you using shell corn or cracked corn?
When you said you made the hole a half in bigger than the rod did you mean a half inch on each side of the rod or a one inch hole for a half inch rod?
I use shell corn . If you want to use a feed or cracked corn just make the hole in the bucket a little smaller .
The hole I use is a 1/2 bigger than the dowl used . So , if I use a 1/2 inch dowl I will drill a 1 inch hole . 1 inch dowl drill a 1 1/2 hole . Should leave you about 1/4 inch all the way around the dowl and enough to bunch up the corn , yet let some fall out when the hit the stick !