Beis Shammai say: A Yisrael may not be invited [to join] with a Kohen in a bechor. Beis Hillel [however] permit [it], and even a non-Jew.  [If] a bechor suffers from a congestion of blood, even if it will die it may not be bled; [these are] the words of R’ Yehudah. The Sages [however] say: He may let [its] blood, provided he does not inflict a blemish upon it; and if he did inflict a blemish upon it, it may not be slaughtered on its account. R’ Shimon says: He may bleed it even though he inflicts a blemish upon it.