The animals were holding a meeting over a serious issue threatening their existence. The cock refused to come as he said to have a private engagement and told the animals that whatever was decided was okay with him . So it happened that the animals needed to do some sacrifice. So the animals decided to use the cock for the sacrifice. The cock was dumbfounded when the animals came to use him for the sacrifice. Now what is the moral of the joke? That private interest should not override public interest.