The slaughtering of what is in the belly of a slaughtered animal is accomplished by the slaughtering of its mother, provided its form is fully developed and its hair has grown.
و حدثني عن مالك عن يزيد بن عبد الله بن قسيط الليثي
ذكاة ما في بطن الذبيحة في ذكاة أمه إذا كان قد تم خلقه ونبت شعره