Welcome to our 3-star walkthrough for Ragnahog level 15. A 4 bird solution for 168660 is shown in the video below.
We send Red up to the first piece of wood to dislodge the pig and stones there, they fall off the floating island to the left. Next, Tony goes under the boat all the way to pop the sea monster right in the jaw, saving the pig from consumption but sending him to meet his maker. Tony falls through the belly of the beast, which collapses to rubble. Third, the boomer bird goes on a shorter trip, under water to the center of the boat like a torpedo, collapsing it as well. Make sure you wait until points stop rolling, sometimes the debris in the water continues to get damage from floating into itself. Finally, send OB back to the upper structure. As a piece-de-resistance, the hammer falls for a couple of extra points.