Charles Ellicott Commentary Leviticus 14:22

"and two turtle-doves, or two young pigeons, such as he is able to get; and the one shall be a sin-offering, and the other a burnt-offering." — Leviticus 14:22 (ASV)

Two turtledoves, or two young pigeons — which were plentiful and cheap in Palestine , instead of the two lambs required of those who were able to bring them.