Leviticus 5:7-8

7‘But if 1he cannot afford a lamb, then he shall bring to the Lord his guilt offering for that in which he has sinned, two turtledoves or two young doves, 2one as a sin offering and the other as a burnt offering.

8He shall bring them to the priest, who shall first offer that which is for the sin offering, and shall pinch off its head at the front of its neck, but he 3shall not sever it.