وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ يَزِيدَ بْنِ عَبْدِ اللَّهِ بْنِ قُسَيْطٍ اللَّيْثِيِّ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، أَنَّهُ كَانَ يَقُولُ ذَكَاةُ مَا فِي بَطْنِ الذَّبِيحَةِ فِي ذَكَاةِ أُمِّهِ إِذَا كَانَ قَدْ تَمَّ خَلْقُهُ وَنَبَتَ شَعَرُهُ ‏.‏

Yahya related to me from Malik from Yazid ibn Abdullah ibn Qusaytal-Laythi that Said ibn al- Musayyab said, "The slaughter of what isin the womb is included in the slaughter of the mother if it isperfectly formed and its hair has begun to grow." Translation Not Available

Book Ref: Muwatta Imam Malik Book 24 Hadith 1054
Web Ref:  Muwatta Imam Malik Book 24 Hadith 9