Hi Stelios, There were two things I was concerned about. One was impaction but I don't think that is the case here as they on Lino and at a good temperature. It may be possible that she is gravid depending on how old she is. The dirty deed could have been done before you got her. If she is you should be able to see two pinky white almond shaped and sized eggs in her abdomen. Lift her up and look at the underside near her tail (don't turn her on her back - they can't breathe) or put her in a clear plastic container if she is wriggly and look from underneath. If she is gravid then she should lay very soon. See SleepyD's sticky on the Breeder section of the forum for more info.
The other possibilities are that she may have parasites - a faecal check at the vets would be advisable. Or she could be being bullied by one or more of the others - not always apparent to us humans.
My advice would be to separate her into an enclosure by herself for a while. If she is going to lay then she needs the peace and quiet. If she has parasites then it will help to stop their spread to the others. If she is being dominated then obviously she can't be if she's on her own.