The only thing I recall about this movie is that it stats as live action in the beginning the movie starts its raining so these two kids go into their attic and find a book the Ugly Duckling as they read the story becomes animated. The Ugly duckling is greyish he also has a lisp. His brothers and sisters make fun of him for being ugly. He accidentally over sleeps when it's time to migrate. On his way south to find his family he stays in a rabbits hole and eventually turns into a swan.

"Timeless Tales from Hallmark" The Ugly Duckling (1990) (http://www.imdb.com/title/tt0310264/reference)