Leviticus 5:7-8

⁷But if he be not able to offer a beast, let him offer two turtles, or two young pigeons to the Lord, one for sin, and the other for a holocaust,

⁸And he shall give them to the priest: who shall offer the first for sin, and twist back the head of it to the little pinions, so that it stick to the neck, and be not altogether broken off.