A mother duck would not see her duckling as ugly. A mother's love does not look at the appearance, but looks at the heart. So, if I were writing a story from the mother's point of view, I would cast the mother as an all-loving duck, an encouraging duck. The mother duck would continually tell the ugly duckling that he is beautiful to her on the inside and out, that outside looks are unimportant and that he should cultivate his heart. In that way, he will appear beautiful to everyone in the only way that really counts. Then, I would make the little duckling embark upon a life of helping others, no matter how much they made fun of him. He would go out, and do good deeds for everyone, help everyone out of a jam, treat them kindly. Then, one day, he sees his reflection in a puddle of water and realizes that he is no longer ugly. His mother's love has transformed him, and his goodness has transformed him, and ugliness has vanished because it was never there in the first place - just a matter of perception.
In the traditional tale, when the duckling grows up and sees who he really is, he realizes he is actually beautiful. In your tale, you can make him realize who he really is INSIDE - so it is a different twist.
What do you think?