(a) When any poultry or other article is detained under this subpart, an authorized representative of the Secretary shall:

(b) If the owner of the detained poultry or other article, or the owner's agent, is not the immediate custodian at the time of detention and if the owner, or owner's agent, can be ascertained and notified, an authorized representative of the Secretary shall furnish a copy of the completed “Notice of Detention” to the owner, or the owner's agent. Such copy shall be served, as soon as possible, by delivering the notification to the owner, or the owner's agent, or by certifying and mailing the notification to the owner, or the owner's agent, at his or her last known residence or principal office or place of business.