Leviticus [Pertaining to Levites] 5:7-8

⁷“‘If he can’t afford a lamb, then he shall bring his trespass offering for that in which he has sinned, two turtledoves, or two young pigeons, to Adonai ; one for a sin offering, and the other for a burnt offering.

⁸He shall bring them to the priest, who shall first offer the one which is for the sin offering, and wring off its head from its neck, but shall not sever it completely.