I have a mating pair of gliders, Princess and Snickers. He is 3 and I have had him since he was in pouch. They have had 2 joeys. I have health problems so I had a lot of time but I was going to start college classes. They were early on pregnant when I rehomed them. I was worried I wouldn't have time for the new joeys. The couple seemed nice and knowledgeable. Plus, I had printed a SEVERAL page guide including each of their individual info.
I had more time on my hands and missed them terribly. With my mother’s intuition I called to check on my babies to find out they were up for sale. I ended up paying more for just them then they did for a huge cage, all their things, pouches, the mating pair and 2 in pouch joeys, which they had also sold. But it was worth it to get them back.
It’s been about 6 wks. and he has lost his bald spot. Princess’s unneutered brother Pumpkin is in another cage in the same room. Pumpkin is showing male behavior so I don’t know why Snickers isn’t. I only have the four suggies and she is my only female. I have been feeding them a very healthy diet. They are in a smaller cage then they were in before and they have been squabbling a little. I am worried those people mistreated him or did something. They said they didn't neuter him but I obviously cant trust them. Does anyone know why his very obvious bald spot has completely filled in?

You might have him checked by a vet to see if he has health issues or if the was actually neutered.

Unless there's something crazy going on, the four reasons a glider would not have a bald spot are:

1. It's a female glider
2. It's a neutered male glider
3. It's a sterile male glider (rare)
4. It's a male glider that is not yet sexually mature

It's possible that Snickers was neutered. It's also possible that the glider you have is not Snickers. The couple may have knowingly or unknowingly switched him out for one of the joeys or another glider altogether. Gliders can undergo personality changes, but if Snickers acts like he doesn't know you, it may not actually be him. :(

I'm glad you got your babies back though, and I hope things get back to normal if he has been neutered. :)