Status of an animal discovered inside a slaughtered animal
Defining the biblical term "Food which Comes from Food" as the case of an animal found inside a slaughtered animal, which would then be the minimum size for Food to Communicate Impurity: Yoma 80a
If a placenta leaves the body before slaughtering, and then returns inside, it is not made permissible with the subsequent slaughtering: Bava Kama 11a
Is there a requirement for shechitah [kosher slaughter] before eating it?: Bechorot 12a