It's been a long time since I've said anything about this funny sketch, but I have noticed something that's never occurred to me before while listening to the soundtrack slowed down. When the other two pigs fall you can clearly hear the noise made by them crashing at the foot of the mountain.
Well when the last one is struck by the boulders it's commonly been assumed that he is crushed or pulped against the mountainside. However I now am convinced it looks more like when the boulder hits him it sends him falling backwards ahead of the avalanche.
This is suggested because listening carefully I can hear his screaming drawn out and cut off by a sudden sharp sound, while the boulders are still in sight just before they roll away. This must be the third and final crash.