In the wild, Sugar Gliders will mate once a year and have only 1-2 joeys at time. In captivity, since it is a controlled environment with their mate always available, gliders will produce all year round. Gestation for the females is about 16 days. Once the gestation period is over, the mother will lick a trail from her cloaca where the joeys will travel up to her pouch. At this stage the joey is only the size of a tiny bean! They will then find a nipple to latch onto and stay in her pouch for a few weeks as they continue developing. 
With the joey or joeys now attached in pouch, you will start to notice mom’s pouch getting bigger over the course of a few weeks. Around 3 weeks is when the babies are visible. 5 weeks is when the tail or feet start sticking out of the pouch. During this stage, the mom will make various “hissing” noises and start to shake her hips from side to side. This is a nursing noise which sounds like maracas! Since female gliders have 2 uteri, it is normal for a mom to have 2 joeys in pouch with different development stages. 
The OOP (out of pouch) is the date when the joey is detached from the nipple and can reattach on their own will. This occurs around 6-7 weeks of development. The OOP date is like their birthdate! This is when you can start tracking their actual age. Their eyes will still be closed, their fur is flat, and they are able to make various noises such as crying and crabbing. The joeys will still be very close to mom and mostly stay nursing from her pouch vs eating any prepared food that your adult gliders eat. 
Their eyes start to open at 10 days old. They will still be nursing from mom but joeys will be able to climb onto dad’s back to allow their mother some alone time to eat and play. 
3 weeks oop is when eyes are fully open, fur is semi fluffed out and joeys will start to cling on either parents while they go out to explore.  
4-5 weeks old, fur is fully fluffed out. Joeys will begin to explore the cage on their own. They are still nursing on mom, but will also test out the main food. 
At 6-7 weeks old, joeys will begin eating more of the main food as well as any treats the parents are eating. 
Joeys are completely weaned from their mom at 8 weeks old. They are able to eat on their own and be independent from both parents. If you are a breeder, you may separate joeys from parents once they are 8 wks OOP, so long as you can observe them eating well and maintaining healthy weight.
Joey Growth Chart
Age  Weight
1 week 12g - 22g
2 week 12g - 26g
3 week 12g - 27g
4 week 23g - 33g
5 week 30g - 40g
6 week 35g - 45g
7 week 50g - 50g
8 week 45g - 60g