It appears now that I have three queenless hives :(
I went ahead and put a frame of eggs, larva and brood from Hive #2 into Hives #1 and #3 to see if they would go ahead and make a new queen. Hopefully, I did not move the queen from hive #2! Hive #2 is still going strong.
However, as I looked into hive #4 I could not find evidence of a queen there either! Yikes, I 'll check on this one again soon.