If she's suddenly decided to go off feed and is otherwise acting "off" I want to say it's most likely an RI over "bad" rats. Though I've never had to deal with an RI in boas I have a new addition ball who's been having a hard time kicking an RI and when he was sick his feeding response was so different than when he was getting better (ie: he would act very scared of his feeder and would recoil from it when ill and strike within a second when feeling better). Good luck!