Um... well if you mean her pouch. I haven't heard of it but, it's possible. If you mean sleeping pouch yes. I had a problem with cannibalization. Why what's your concern.
I have never heard of it happening, but, that doesn't mean that it couldn't. Are you just curious or is your female attacking her babies? What's going on?
Like I said, I have never heard or read of a mother cannibalizing her joey's while still attached at nipple. It usually happends a few days to even weeks after the joey's are oop. I am saying it is possible because, if the mother can sense something is wrong with one, she may try to kill it to save the other, same with stress or even if she is sick. There are many different reasons. The joey's body will come oop but the head will stay in attached to the nipple. That is why I am saying it is possible. But, anything is possible. There are many good websites about cannibalization if you would like to know more.
Cannibalisation can happen at any stage, from the moment of birth right up through weaning, although cannibalisation at such a late stage isn't really as common. Unfortunately it's something we have to learn from and accept. If cannibalisation is happening the question is why, sure there might have been something wrong with the joey, or something around the cage might be stressing the adults, the diet might not be quite right causing a lack of milk, they might have felt threatened by something (family dog maybe), cage too small. We need to look at external reasons before putting it down to a poorly baby.
So if your adults are killing/eating their joeys look at their environment and diet first. Hope that helps a little. )