Good job taking it in and congrats on the new pituophis! Looks like you scored a nice little albino annectens there. While it will get a good bit beefier than the average corn, they don't get much longer with most adults maxing out right around the 5 foot range.
I start most of my pits on f/t rat pinkies. Those that don't take the rats usually accept a f/t mouse fuzzy or hopper. In the rare occurrence of a hatchling not feeding on f/t straight out of the egg, an appropriately sized live mouse hasn't failed me yet.