One strategy for Angry Birds Free Bad Piggies level 21-1 is to blast top-left, bottom-left, and top-right piles of stones, in that order. This can cause very significant damage and earn you plenty of points.
This is Level 20-3 from Bad Piggies in the full Angry Birds app. Feel free to check out that page for more strategies.
If you have a different method that is easier or yields a higher score please feel free to leave a comment below explaining your strategy. Please don’t post your score in the comment section without an accompanying explanation on how that score was achieved. For those looking to post individual scores, head on over to the leaderboards and compete with the rest of us!
1. Bomb Bird into the top two small stone square blocks on the upper structure. The upper right pig needs to be destroy and sand bag needs to fall. Point over 70k are desired.
2. Bomb Bird into the top two small stone square blocks on the lower structure. Then start to pray for a good debris fall.