From Section 21.13 - Permit Exceptions for Captive-Reared Mallard Ducks, Part B:
(b) All mallard ducks possessed in captivity, without a permit,
shall have been physically marked by at least one of the following
methods prior to 6 weeks of age and all such ducks hatched, reared, and
retained in captivity thereafter shall be so marked prior to reaching 6
weeks of age.
(1) Removal of the hind toe from the right foot.
(2) Pinioning of a wing: Provided, That this method shall be the
removal of the metacarpal bones of one wing or a portion of the
metacarpal bones which renders the bird permanently incapable of flight.
(3) Banding of one metatarsus with a seamless metal band.
(4) Tattooing of a readily discernible number or letter or
combination thereof on the web of one foot.
It states in the General Provision of the Waterfowl Sale and Disposal Permit that:
(2) All live migratory waterfowl possessed in captivity under
authority of a valid waterfowl sale and disposal permit shall have been,
prior to 6 weeks of age, physically marked as defined in Sec. 21.13(b).
(b) All mallard ducks possessed in captivity, without a permit,
shall have been physically marked by at least one of the following
methods prior to 6 weeks of age and all such ducks hatched, reared, and
retained in captivity thereafter shall be so marked prior to reaching 6
weeks of age.
(1) Removal of the hind toe from the right foot.
(2) Pinioning of a wing: Provided, That this method shall be the
removal of the metacarpal bones of one wing or a portion of the
metacarpal bones which renders the bird permanently incapable of flight.
(3) Banding of one metatarsus with a seamless metal band.
(4) Tattooing of a readily discernible number or letter or
combination thereof on the web of one foot.
It states in the General Provision of the Waterfowl Sale and Disposal Permit that:
(2) All live migratory waterfowl possessed in captivity under
authority of a valid waterfowl sale and disposal permit shall have been,
prior to 6 weeks of age, physically marked as defined in Sec. 21.13(b).