A Kohen is believed to say, “I showed this bechor [to an expert] and it is blemished.” All are believed concerning the blemishes of the maaser [offering]. [If] a bechor’s eye was blinded, its foreleg cut off, [or] its hind leg broken, it may be slaughtered by the decision of three laymen. R’ Yose says: Even if there are twenty-three, [it] may not be slaughtered except by the decision of an expert.