Hey,
I would not worry to much about her weight if she is generally, in good health and also, carrying good weight on her too. Typically speaking she is not in breeding condition and should not be for a while longer, because she is only as you described a yearling. Animals do not for the most part, come into breeding weight and size if all parameters were kept ideal and proper till she is at least 3 years old. It can be some thing other than her desire to just quit feeding that triggered her spontaneous fasting; husbandy issues come to mind.
Some times they and other boids do go off feed spontaneously, like Ball Pythons, that come into a fasting period with no changes in husbandry having been made. All things considered, as long as the SST, is not showing signs of distress and or RI, or any thing other than the two things listed, I wouldn't worry about it too seriously. They will resume feeding, usually, when she or he, is good and ready. Some times feeding at different times of the day can elicit a feed response when you shift the feeding time to another time in the day; particuarly at first lights out; the twilight hour. That is when they are most likely to respond to feeding.
You might also, want to try feeding large adult mice - as apposed to rats. If you are feeding F/T, be sure to warm the food up as the best feeding response will be had when the food is warm as the heat sensory facial pits, are brought into play more readily when the food is warm and giving off infred signals.
Check the hide spot, check for possible changes in the husbandry; temperature changes - even changes in the food can make the difference. Fresh kill, versus, warmed and thawed F/T, food. Is it kept in a quiet room or one that is more likely busy and noisy and trafficked oftened with lots of disturbance. Try leaving food outside of the hide spot or in the hide spot that has been warmed and dried. Some animals will not eat wet food after soaking frozen mice or rats; some will regardless. At any rate, if the SST, does not eat right away for you, just keep feeding trials at a regular schedule. Give it a week, and then retry again and see what the feeding respone is then. If it ate for you before it will eventually eat again; provided there is no underlying illness. The key is to not give up prematurely. Good luck. Could it be in shed and you missed that?
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