One simple trick to find the hidden unread message in iMessages on your ipad!
There was a little red circle with a 1 in it. Showing that there was one unread iMessage. But I could not find it! I scrolled up and down and could not find the unread message.
The trick is to ask Siri to show you your unread iMessages. I hit the siri button and asked that and it read me the unread message and boom, the red circle was gone.