The subject says it: Is it allowed to count the remaining stack of chambers during the game?
I assume yes, because you can deduct from the amount of already placed chambers to the amount of remaining chambers in the stack, anyway. Just want to be sure.
Of course you are not allowed to look at the remaining chambers or to change their order.
The stack is sitting in the middle of the table within reach of everyone. You could count it as is due to the tile thickness so there's nothing wrong with that.