Yosef Karo, Shulchan Aruch — Yoreh Deah 15 To not shecht a beast until its eighth day
“ To not shecht a beast until its eighth dayשלא לשחוט בהמה עד יום שמיני ללידתהContains three Seif.ובו שלושה סעיפים:Seif 1 A chick: As long as it hasn't emerged into the world's airspace it's forbidden, and after it emerges in the atmosphere it's permitted immediately.אפרוח: כל זמן שלא יצא לאויר העולם – אסור, ולאחר שיצא לאויר העולם – מותר מיד.Seif 2 A beast that gave birth: If it's known that it completed its term, namely nine for a cow or five for a sheep/goat, it's permitted immediately the day it's born, and we need not worry that its parts got crushed in the birth labor. ”
