It can happen it could have some kind of bug. I have an 03 normal female she eats every week small rats. She only weighs 1166g Ive had her to the vet nothings wrong with her. I have her sister too and she is my biggest female at 2549g. I was hoping to breed her this year but still a bit to small for me. I have an 06 female that is only 100g bigger than my 07 male pastel. she has never missed a meal. They are like people (kind of) some grow bigger,faster. Some stay smaller,thinner. There might not be anything wrong with your snake. Could just be small, but then again there could be. Getting it into a good vet will be the only way to tell. Getting a good scale also will help telling if shes 600g or over 1500g. Like asked before can you take a picture of her next to something so we can try and guess the weight. Put her down and set a pop can by her just so we have something to compare her to. Would help us guess her weight. My 600g or even the 700g are thinner than a pop can. If shes bigger than a pop can is round then. I would guess she should be atleast over 1000g.
