Siman 310

A bekhor that had a permanent and visible blemish and they slaughtered it before showing it to a sage or to three members of the synagogue, even if he showed it to a sage afterward and he saw the blemish, it is of no avail; it is forbidden for benefit and requires burial, the meat with its hide. There is no distinction whether one acted intentionally or unintentionally, whether the owners or the kohen slaughtered it or it was done by another; since it was slaughtered before the inspection of a sage or three members of the synagogue, the sages forbade it for benefit. The reason for the decree is because there are blemishes that change after death, appearing as a blemish while in life they were not truly a blemish; therefore they decreed regarding all blemishes (as Rabbi Meir, 28). And even though the Tosafot there ruled like Rabbi Yehuda, and such is the opinion of Rav Shmuel ben Hofni in the Tur, nevertheless the Bahag, the Rambam, the Ramban, the Rosh, the Tur, and the Shulchan Arukh ruled like Rabbi Meir. So too wrote the She'iltot, Parshat Bo; and it is a wonder regarding the Tur who wrote in his name the opposite, see there.

Therefore, one who slaughters a bekhor without the authorization of an expert and sold it and received payment, even if the buyer consumed it, the seller must return the payment to him. And even though this is only a rabbinic prohibition, and it was explained above in siman 119 that regarding a rabbinic prohibition when one has consumed it he does not return the payment, even when he consumed it, the hide requires burial. And if they made shoes from the hide or another object, they must bury them. And similarly, when he has not yet consumed it, the meat requires burial, and he shall return it to the owners so that they may bury it, for the mitzvah is incumbent upon them (Taz, subsection 3), unless he is suspected of selling it once more after he buries it. And the owners of a bekhor are the kohen. And it is obvious that if he sold it intentionally, one should not return it to him, for he will certainly sell it once more as he did the first time. And the vessels in which they cooked it require koshering.

One who is not an expert and saw the bechor and permitted slaughtering it, and it was slaughtered based on his word, it must be buried and he must pay from his house (Mishnah ibid.). And how much does he pay? It is stated in the Gemara there that he pays a quarter for a small animal and a half for a large animal. And Rashi explained that it is money cast in doubt, for perhaps it was not a complete mum and a mum would never have occurred in it, and he did not cause him a loss at all; or perhaps it was a complete mum and he caused him to lose it entirely; therefore he pays half. And it is not because "money cast in doubt is divided," but rather thus the sages enacted regarding a bechor (Tosafot ibid.). And for a small animal, half of a large animal, because they do not raise small animals in Eretz Yisrael and its care was burdensome, and they saved the kohen from great toil, and half of a large animal is sufficient (Rashi). And according to this, in the diaspora, even for a small animal one must pay half its value. And nowadays, since even in Eretz Yisrael most fields do not belong to Israelites and it is permitted to raise small animals, therefore now even in Eretz Yisrael he pays half its value. (And the wording of the Rambam in chapter 3, halacha 6: And for what reason does he not pay all its value? Because they penalized him, etc., and one may not raise small animals in Eretz Yisrael. Thus far his words. And it is not understood regarding a large animal why he should not pay all its value, and if he has a reason for a large animal, why did he not explain it? And also the Mishnayot require further study; see there.)

There is one who says that an expert individual who saw his own bekhor—even though it will be explained in siman 312 that one may not examine his own due to suspicion—nevertheless, since it is only due to suspicion, we do not forbid it ex post facto (Pitchei Teshuvah in the name of Brit Avraham). These are matters of little consequence, for behold, nowadays there is no expert, and if it was permitted by one, it is as if it was not permitted at all. And if it was permitted by three and he was one of the three, it is obvious that it is permitted, and perhaps even initially he may be one of the three, and it will be explained there. And it appears to me that when the sage saw the blemish in the hand of the kohen, even though he has not yet brought witnesses that it fell on its own, this is not relevant to the permitting, and there is a proof from Beitzah 27, see there.