For starters, what do you mean by "ground feed"?


Are you talking about finely ground feed (through a 1/4" or smaller screen)?   Or "cracked corn" mixed with pellets?



Finely ground feed will absolutely go out of shape faster than shell corn will and the time frame is shorter the finer it is ground.

If you are bagging it in paper bags (no plastic) that can breathe, that will help.   Also you have colder temperatures on your side.

During warm/high humidity months you really don't want ground hog feed around much more than 10 days-2 weeks.