Hi Clair —
I claim no experience with predator feathers or confiscation procedures, but would offer a few thoughts in regard to the general challenge of dealing with any bureaucracy in matters concerning the interpretation or enforcement of codes, regulations, etc.
Try to arrange a face-to-face meeting with an agency representative — preferably someone at a decision-making level and not merely a person behind a reception desk.
Present your case as objectively and factually as you can, and with as much supportive documentation as possible. Avoid getting into an argumentative mode which will only trigger defensiveness on the part of the individual you’re dealing with.
Ask about what, if any, channels and procedures exist to make amends for whatever action or inaction on the part of your institution or its representative(s) may have led to the confiscation, or about channels and procedures for appealing the bureaucratic decision to confiscate.
Assuming that you’re dealing with a state or federal agency (or maybe some of each), get in touch with your legislative or congressional representative and ask how best to proceed. That person may be able to refer you to a colleague who sits on the legislative committee charged with oversight of the very agency you need to deal with. Such an individual should have a detailed knowledge of the ins and outs of pertinent laws/mandates/regulations/codes, etc., and whether there may be some procedural “workaround” option. A letter or phone call of support from such an individual to an agency administrator can sometimes work wonders.
Although I can’t speak to the specifics of your situation, I’ve have had numerous occasions to deal with bureaucratic organizations at various levels, and have found these approaches to be helpful in most instances.