Answers (3)
Did you just get them or have you had them for awhile?there could be something going around that they got ahold of a virus or some bacteria at this point it could be something they caught from the air call the place where you got them and ask them about any sickness you can even call an exotic pet store and ask.
It depends what kind of geckos u have. My gecko (Tokay) is nocturnal, so he only comes out at night. They might be hiding because they r getting used to their new environment and surroundings. U also might not be giving them the proper food (Note: Almost all geckos favorite foods are crickets and mealworms) Don't forget to hydrate them! ;)