This is a random stage with moving targets. Your goal is to kill as many pigs as you can with each of your shot. The best way is to target the bomb on the floor and hope that the flying debris can kill the flying pigs.
You should at least kill 4 pigs with each shot and try to end the stage with at most 4 shots to get the three star ranking. Because this stage is very randomized, so that the angle and the power usage all depends on your situation.
In general, aim for the pigs that carry stones as the flying stones can usually kill more pigs.
First Shot Result
Second Power Activation Point
Second Shot Result
Third Power Activation Point
Third Shot Result