When do I consider oop date? Our joeys started making an appearance yesterday. I can see full body but have yet to see the head. I did see pouch fully open and seen 2 joeys inside. The joeys I seen looked same size but one side of pouch is bigger. Could there be a 3rd Joey?

I think there are 4 nipples, so theoretically there could be more than 2 joeys.

The OOP date would be when you first see the joey completely out of the pouch. I think.

The OOP date is the day when they fully go out of pouch, it's practically impossible to observe it though, which is why it's almost always an approximative date.

There can be joeys from different ages in the pouch, which could explain the difference of volume on one side, but a simplier explanation is that the way the joeys place themselves there could also explain it.