Unfortunately it is true that kindness being paid to others is not always returned immediately, but I am so very proud of you for wishing to return a lost infant to its mother. Animals of more instinct-driven intellect are sometimes driven to, in the case of large litters or harsh times, abandon the least capable of their young so that they may ensure the survival of others, or if things are considerably bad, themselves. I'm still certain that involving Fluttershy was the correct thing to do, and I know that you desiring to care for such a being likely helped strengthen your friendships.