Continuity mistake: When Jerry slips a photograph of Tom placing the chicken under Spike's arm in the cake, he inserts it with the printed side up. When Tom lifts up the cake, the photograph is now completely blank.
Continuity mistake: When George is at the fridge and finds the chicken has been eaten, the door is open. But in a close-up of Tom in the next shot, the door is now closed, and in the shot after that, the door is open again.