I was just wondering if your cornsnake may refuse it food if the pray item is to small.
I find with my snake recentley he will eat then wont eat for up to 3 weeks. He is currently on 2 pinkies but has taken fuzzy before. Then he dropped back onto the pinkies again
I am having the same problem but don't think its the size of food. Mine as not eaten for a few months but seems healthy enough but i wish he would eat so i can relax.