This guide is identical to Mob Of The Dead (Black Ops 2), Difference is we are dealing with dragons head. Same procedure, feed 10 to 15 zombies.
First Location, Control Room. Go straight at the back. Once you kill a zombie near that statue, it come alive and second kill. He will suck the dead body and ate it. Once you complete this, the dragon head will be back to stone then it will breaks up. This step will be the same on the second and third location. TIP: Wait for the dragon to swallow the zombie before you kill another one.
Second Location, Lower Courtyard. It’s after Double Tap next to the mystery box.
Third Location, Basement. It’s just next to the pyramid.
Once you complete this all three dragons, you will hear a word from one of the character means that you complete all three. To get the Bow, you need to go Altar. This altar location is on second lower basement and the Wrath of the Ancients bow will be behind on that.
Note: This can be done in any orders.