Chullin 21b חולין כ״א ב

from non-sacred animals and not from an animal purchased with second-tithe money, and it is sacrificed only during the day, and with the right hand of the priest, so too, a bird burnt offering comes only from non-sacred animals, and it is sacrificed only during the day, and with the right hand of the priest.

The baraita asks: If so, perhaps just as there, with regard to an animal sin offering, slaughter is valid with the cutting of the majority of two simanim, the windpipe and the gullet, so too here, with regard to a bird burnt offering, the pinching is valid with the cutting of the majority of two simanim. Therefore, the verse states: “And pinched off its head…and burned it on the altar” (Leviticus 1:15). This indicates that just as with regard to burning, the head is burned by itself and the body is burned by itself, so too with regard to pinching, the head remains by itself and the body remains by itself.

Rabbi Yishmael says: “According to the ordinance” (Leviticus 5:10), which is written with regard to the sliding-scale bird sin offering, means according to the ordinance of the bird sin offering mentioned in the previous verse. Just as a bird sin offering is pinched adjacent to its nape (Leviticus 5:8), beneath the occipital bone, so too a bird burnt offering is pinched adjacent to its nape, beneath the occipital bone.

If so, perhaps just as there, with regard to the bird sin offering, he pinches and does not separate between the head and the body and leaves one siman uncut, so too here, with regard to the burnt offering, he pinches and does not separate between the head and the body and leaves one siman uncut. Therefore, the verse states: “And the priest shall bring it,” meaning that a bird burnt offering shall be sacrificed in a unique manner, not like the sin offering.

Rabbi Elazar, son of Rabbi Shimon, says: “According to the ordinance” means according to the ordinance that is written with regard to a bird sin offering. Just as there,