the food item should be about as big around as the diamater as the largest part of your snake. offer a mouse every 5 days and if she doesn't take it right off, leave it over night. my snake will only eat eat in the dark with nobody in the room. (thats why i feed in the evenings, just incase i have to leave it in there, it won't be long before lights out) they are just shy eaters. if she still doesn't take it, just wait till next feeding day to try again.