Sugarglider

Question
My sons 6 month old sugar glider is acting strange.. She is like cramming her head against the cage and she may be sick. She also is cilinging to the cage and will not eat.

Answer
Hello, sorry to hear about the glider. I need to ask a few things but I'm pretty sure I know whats wrong already. Is the glider kept alone? whats the dimensions of the cage as well and how many toys are in the cage and how often are they changed out? And what is her everyday diet?
  Many people are not told when they buy a glider that they stress very very very easily, I always joked with people that bought them from me that even breathing on them wrong will stress them and its almost true. Its insane how easily they stress and yours sounds stressed.
  Gliders that are kept in to small of a cage, kept alone or do not have enough toys or those who's toys are not regularly changed will stress. Gliders HAVE to be kept in pairs or a group, unless you can devote a minimum of 4 hours to the glider EVERYDAY it will eventually become stressed if kept alone. Also the minimum cage size for one glider would be 3 foot tall by 2 foot long by 1 foot wide. They need a lot of cage space and new toys every month.
  They are very cute and fun pets but are not cheap at all and are not easy pets, I generally do not sell mine to shops or people under the age of 18 due to the fact that most people really don't know how to care for one in a way that will keep them happy and healthy.
  If she is stressed she needs to see a vet asap. A stressed glider can self mutilate and will chew off their own limbs. I have about 6 right now who are missing tails or feet due to this and all were kept as a single glider. I would take the glider to the vet regardless just to see what they say, usually gliders will show you they are sick, they will have goopy eyes, sneeze, have a wheeze or will gag or vomit in a sense. Be prepared for a bill though, most vets will say they are sick even when they are not and will keep them over night on IV fluids and will rack up your cost and you still end up with a "ill" glider. I learned that the hard way with my first one and finally took her to a breeder and she told me she was stressed and she kept her with her group and she was fine within a matter of days. If you cant afford a large vet bill see if you can contact a local breeder in your area and get some help from them. They can tell by looking at the glider what may be wrong, whether it be stress, improper diet or illness.