this is more about the mouse but from what i've seen, they seem to like oatmeal alot. anytime i have to keep a mouse for a few days i give them a mix of bread, cheerios, and oatmeal which is probably more than most ppl are willing to do for feeders but the oatmeal is always gone first. u can get like a bucket of oatmeal for about $2-3 and it'll take forever for it to run out on top of it staying fresher for alot longer and having more nutrients.