Parashas Vayikra · Aliyah 4 · Passuk 9
Chabad.org — English translation + Rashi
Torah Temima points to Toras Kohanim / Chullin on the alyah of sheep.
E-Daf / Tsurras Hadaf
PDF of the daf / source
English: Its fat: the whole fat tail, he shall remove it opposite the backbone.
Additional emur unique to sheep — the alyah is removed in one piece.
For a sheep shelamim, the entire fat tail is taken as part of the altar fats, cut away opposite the backbone, together with the other chelev of the innards.