Continuity mistake: When the dog drops one of the chicks after rounding the others up, the position of the chick changes between shots.
Continuity mistake: When Foghorn Leghorn is watching the dog marching, he is holding some corn on the cob in his hand. But when he is marching along with the dog, the corn is nowhere to be seen.
Continuity mistake: When we see the dog marching at the start of the cartoon, you can see the fence behind him is made of wood, but when he turns and marches back, part of the fence has been replaced with fencing wire.
Continuity mistake: When Foghorn Leghorn lifts the wired fence with his foot to let one of the chicks out, you can see there some chicks by his foot when he lowers the fence down, but in the next shot the chicks have disappeared.