When the laws painted on the side of the barn are read for the first time, in the close-up shots some of them are already in the altered forms they take later in the movie.
When the animals discover Old Major's head while exploring the butchery, they all flee. In one shot, Jessie is running amongst the other dogs. Jessie was inside the barn giving birth at the time, and would not have been present when the other animals were in the house.
In most of the shots of Jessie where computer technology added in her mouth movements, her black pigmentation above the left side of her nose was added on the right side instead. Her markings are correct, but her nose pigmentation is flipped.
Flipped Image: At the end of the film's introduction, just before the title appears, the close-up of Jessie's face as she says, "But I could still remember," is flipped. The markings that are on the left side of her face are on the right, and the markings that are on the right side of her face are on the left.
Flipped Image: The scenes before the duck that witnessed Boxer's collapse flies toward Jessie, Benjamin, Clover, and Muriel, are flipped. Jessie's markings are opposite. Also, the close-ups of Jessie as she turns and listens to the duck are flipped, and the scene of her and Benjamin running back toward the windmill are flipped as well.