New Baby Died:):) Don't know why?

I'm so sad my daughter got an indian redneck parrot from a breeder and in less then 24 hours it died. It did not look right to me....although I've never owned any bird....the breeder said it was picked on by it's siblings and was "weak and timid". It was missing feathers from its head and body (she stated due to her siblings) and initially unable to perch it seemed she had loose poops. My daughter was diligent in contacting the breeder for support and and was consistently reassured the bird was fine. The breeder did refund the money but was rather defensive and unfortunately not comforting. I am so sad and confused, that bird was so beautiful.
Does anyone know why is would have died?