I know with my problem-child Kingsnake I have to wait a minimum of ten days, preferably two weeks, after a regurgitation before I feed her again. Not sure if you're doing that, or not, but they need time to regrow gut flora, to my understanding, before they can be fed again. If she hasn't digested her meal by day 4, she may not have enough gut juice to digest it properly. My kingsnake female has been diagnosed as having a defect in her digestion - she's a year old, and only 31g. The male I got at the same time is the same age, and 110g. Also, apparently once some snakes start regurgitating, they might keep doing it. My girl will go for six to ten meals, seem to be fine, eat voraciously and poop regularly, but she doesn't put on any weight and she'll spontaneously regurgitate again after two months of eating fine.