Yahya related to me from Malik from Nafi that Abdullah ibn Umar
said, "When a she-camel is slaughtered, what is in its womb is
included in the slaughter if it is perfectly formed and its hair has
begun to grow. If it comes out of its mother's womb, it is slaughtered
so that blood flows from its heart."
Muwatta Malik Book 24, Hadith 9