I would suggest getting a fecal done to see if she has an overload of parasites causing her a hard time to maintain weight. If you catch it early enough it's not a big deal, they can even give you a powder formula that you syringe feed to keep them going. Otherwise they could start to have kidney problems...
Other then that, it's normal for geckos to go off feed once it starts getting cooler. As long as they are not losing weight I would not worry about the feeding response.. but I would be very cautious with the smaller gecko.
GL
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