This is an appendix post for the article "All Quacked Up: Steve Gerber, Marvel Comics, and Howard the Duck" (click here).
Disney apparently regarded the appearance of Howard the Duck as a potential infringement of their trademarks for Donald Duck and other duck characters. Marvel agreed to modify the visual depiction of Howard to placate them. Disney’s art department produced these model sheets to illustrate the approved changes.
Model Sheet 1
Model Sheet 2