The obligation to give the gifts rests on the animal’s owner. If he gave the animal to a shoḥet to slaughter on his behalf, the shoḥet takes responsibility for distributing the gifts to a kohen and must ask the owner to which kohen he wishes to give them (see SA YD 61:28).
It is a mitzva to give the gifts in a respectful manner, immediately after slaughter. A kohen may therefore not assist the owner or slaughterer in order to steer the gifts toward himself; he may not even ask for them, let alone seize them (MT, Laws of Firstborns 1:14; SA YD 61:11). The gifts may not be divided into portions so small that no kohen receives a meaningful share (SA YD 61:9).
If no kohen is present, the gifts are assessed for their value and the owner may eat or sell them, paying their value to a kohen afterward. This prevents the kohen from losing his gifts, since if left uneaten the gifts would spoil (SA YD 61:10).
According to several Amora’im, one may not eat the meat of an animal from which the gifts were not given to a kohen. In practice, however, such meat is permitted. Still, it is a pious practice not to eat meat from an animal whose gifts were not given to a kohen (Megilla 28a; Ḥullin 37b; Tosafot, Ḥullin 131a, s.v. hachi garsinan; SA YD 61:5).
If an owner refuses to give the gifts, a beit din with the authority to do so may compel him (Taz 61:17). If he violated the law and ate the gifts, sold them, or discarded them, no particular kohen can claim reimbursement in court. Nevertheless, he is obligated by Torah law to repent and give their value to a kohen (SA YD 61:15).
One may not purchase or receive as a gift the foreleg, cheeks, or maw that were not given to a kohen, since doing so makes one a partner in depriving the kohanim of what is theirs. After the fact, if a Yisrael already has such meat in his possession, he may eat it, since the duty to compensate the kohen falls on the animal’s owner (SA YD 61:31). Even so, the pious practice is to avoid eating meat from an animal whose gifts were not separated — and one certainly may not eat the gifts themselves when they were taken from the kohen without his consent.
