The girl-fox on the streetcar sits down, but the animators forgot to draw the bench. (In the next shot, she sits down again, but this time the bench is there.)
The first shot of the hobos shows a pot with a fire going underneath. In the next shot of the hobos (from the same angle), the pot is missing, leaving an empty space on the right side of the screen. In the third shot, the pot is back, but there's no fire underneath (even though a hobo tells the singing chicken inside to "boil, darn ya, boil").