I've never heard, read, or been informed about any regulation in Indiana regarding an empty/filled chamber. Just like the question of open vs. concealed carry, use your own good judgement, since they're both legal.
I have a DAO revolver with no hammer spur and a hammer safety. There's no way for the hammer itself to reach the firing pin, even if you literally took a hammer to my hammer. It's inherently safe, so I carry a round in every chamber.
Now, if my revolver was an older style where the firing pin was an integral part of the hammer and the spur stuck up, I'd prolly leave the chamber under the hammer empty.