Do I need a taxidermy license if I am only preserving skulls and antlers for a profit?

Yes.  You must apply for and purchase a Taxidermy License available at any IDFG office.  The license is issued on a fiscal year basis (July 1-June 30) and is available on an annual or 5-year basis.  For more information, contact your nearest IDFG office. The application form is available here: http://fishandgame.idaho.gov/public/licenses/furbuyerLicenseApp.pdf