The goal of this shot is to take down the metal link trapping the magnet. To pull this off, aim the pig at the twin yellow birds.
Power Activation Point
A little distance away from the yellow bird, tap the power up to kill the red bird on the first plat form. The force from shooting the gun should push your pig upward, breaking the metal link and kill the twin yellow birds.
First Shot Result
The magnet breaks free from the metal chain, drop down and pull all the metal bars upward. The pulling force will kill the rest of the birds.