Continuity mistake: When Wilbur is meeting Charlotte's three daughters in the barn entrance, the medal that the farmer hung there keeps appearing and disappearing between shots, though the duration of the scene.
Continuity mistake: When Fern is celebrating Wilbur's two-week birthday, he is much smaller in size than in the song scene that played prior to the birthday.
Continuity mistake: They mention that the goose has hatched out 7 goslings. They say there were 8 eggs and one didn't hatch. The one egg is given to Templeton, and it is later smashed open. Later that night as they're going to sleep, the mother goose has 7 goslings under her, but then then it shows Jeffrey (one of the goslings) sleeping with Wilbur. Seems they had an extra gosling with the mother.
Continuity mistake: At the fairground in the scene surrounding Wilbur getting his medal, Fern's mother is wearing a hat with two blue flowers on it. The flowers fluctuate in size during this scene.
Continuity mistake: When the pancake lands on Wilbur's head at the dinner table, it at first has butter dripping off it, but in the very next shot has syrup dripping off it instead.
Continuity mistake: When Fern is outside talking her father out of killing Wilbur, her little brother is inside coming to eat breakfast. His plate is empty at first, then has pancakes on his plate and the next shot he is putting the pancakes on his plate.
