One mouse, matched to the snake's width
A corn snake's meal is one mouse, and the size of that mouse follows the snake rather than the calendar. The working rule is a prey item about as wide as the widest part of the snake's body, or a touch wider — enough to leave a gentle bulge after swallowing, never a strained one. Hatchlings start on the smallest mice and step up through the sizes as they grow, and jumping a size too early is the commonest cause of a refused or regurgitated meal, so let the snake's girth, not its age, call the step-ups. Serve the meal in the enclosure or a bare feeding tub, consistently, so the snake builds one clear association with feeding time and place.
Weekly for the young, slower for adults
A growing corn snake eats every five to seven days, which means most of its weeks hold exactly one feed. An adult in maintenance condition stretches that out to every seven to fourteen days, and feeding an adult weekly out of habit is how corn snakes quietly become overweight — visible in a rounded, soft body and a thickened back half. Fresh water, changed regularly, is the one item that belongs in the enclosure every single week regardless of the feeding schedule. Growth in the first part of a corn snake's life is fast enough that mouse sizes step up regularly, sometimes every few feeds, which is another reason the log — not the calendar — should drive the shopping.
Frozen-thawed, and quiet days afterwards
Frozen-thawed mice are the practical standard: safer than live prey, easy to store in the right sizes, and accepted readily by almost every corn snake. Thaw completely and warm the mouse in warm water so it feels lifelike, then offer it on tongs in the evening. After a feed, give the snake two quiet days without handling — a meal disturbed too soon can come back up, and a regurgitation means waiting well over a week and offering a much smaller mouse before feeding again. Note a shed when it happens, too; many corn snakes refuse food while their eyes are clouded, and that refusal is normal. Warm the mouse in water, never in a microwave, which cooks the outside while leaving cold spots that put snakes off and can burn a mouth.
Watching the pattern across weeks
One keeper's vague memory of who ate when is how snakes get double-fed by one family member and forgotten by another. A written log of each feed, refusal, and shed builds the real picture: steady growth in a youngster, stable weight in an adult, and any change standing out clearly against the routine. It is also the record a vet will want if appetite or weight ever becomes a question.
That log works when it lives in one shared place rather than in the head of whoever happened to feed last. KinsLe's Care Teams keep the corn snake's feeding record as part of its care duties, so each meal and shed is noted once, by the person who was there, for everyone to see.