Getting your new guy vet
checked ASAP, as mentioned above, is importantant just for the fact that he is new. The vet
could check for any possible medical problems that may be causing him to obsessively chew to the point of drooling. I would also speak to the vet
about his unknown previous tail injury. It makes me wonder if he had an accident or if he chewed his own tail. With rescues... you may never know. If the vet
gives him a clean bill of health, you might want to look at all of the other factors that may be stressing him.
There should have been a quarantine period of 30 days to protect your own original 5 gliders that you have, but it seems that they are all in the same room already. Gliders do chew from stress and Duke being re-homed is most likey causing stress for him. Intact mature males sometimes chew on their cages when they hear, see, or smell other intact "New or Different" males in their living area. It is their area, even if they are the one that is new, lol. Dukes being re-homed with his mate and two young joeys is a big stress for any male. Putting him in the same room with new gliders and other intact males might be a bit much for him. He is prob protecting his joeys and trying to keep the other intact males away from "his" girlie. Are any of your orig 5 gliders intact males? How are they behaving towards the new gliders?
I have a 5 year old male that will chew/attack the cage bars and scent mark relentlessly if he can see, hear, or smell another new glider. His behavior is worse if it is an intact male. He is my only glider that can't be in the glider room with the others. He acts as if he can be the only one I own. I keep him and his companion on the main level of my home, away from the others, so he can "relax" for lack of better words. He still knows if there is another new glider upstairs in the glider room and gets aggitated even if they aren't near him, but it isn't as bad as I have seen him when he is in the same room. I feared that he would break his teeth or hurt himself of I didn't move them.
Stress can negatively affect gliders, so I would try and reduce some of his stress if you can. I would hate to hear that something happened to those babies. Can you place their cage in another room away from the other gliders? You could also try covering his cage on three sides and top (leave front open) with a large piece of fleece. This may make him feel more secure and will keep his scent enclosed in his cage. He still needs to adjust to his new home and human family. Giving them some space while they are raising their young joeys in a new home might be a good idea. Introducing him later to the others (glider room) might be easier after he is neutered and his joeys are weaned. Good Luck!!