Snowball did it. He must've put them down the well.
Where did the keys go?!
We have Thwarted Snowball's evil plan!!
Someone must've gotten the keys out of the well!
I can't believe Snowball did all these crimes.
Two legs good, four legs bad. Two legs good...
Comrade, Snowball is very wicked, and wants the farm to fail.
In this scene the animals are blaming Snowball for dropping the keys down the well. As the reader we know this assumption must be false just like all the other ones.
In this scene the animals find the key underneath a sack. They still believe Snowball drained it down the well, and use the excuse that someone must've gotten it out. Even though as a reader we can conclude that an animal just misplaced it.
This strip has dramatic irony because the reader knows that Snowball couldn't have put the keys down the drain, even though the animals believe that.