At the beginning of the movie Beth loads a large blue cooler and a smaller red one into the back of her jeep. They are nowhere to be seen when Boog jumps into the back a few minutes later.
When the dam bursts, Shaw's truck would not be able to surface much less continue to run. The engine would almost immediately cease to work after taking in water through the air filter.
Serge the duck says only him and Deni were left after hunter shot their flock. But later in the movie many ducks including Serge and Deni are seen carrying skunks during the fight.
Good thing that the hunters shot only "their flock" and not the rest of the ducks in the country, too.
At the beginning of the movie, it's 3 days to the open season. It actually takes 4 days, though.