cowsay has many questionable files that could attract copyright and trademark enforcement action. For further details see the pull requested linked below.
Guix packages cowsay. /gnu/packages/games.scm says that the source code repository used is <https://github.com/tnalpgge/rank-amateur-cowsay>. In that repository's CONTRIBUTING.md it says "Issues and pull requests on that repository will be ignored.". I submitted a pull request <https://github.com/tnalpgge/rank-amateur-cowsay/pull/4>. I expect that it will be ignored. I have also found a fork of cowsay <https://github.com/cowsay-org/cowsay> that claims to be maintained. I have submitted a pull request to it as well. <https://github.com/cowsay-org/cowsay/pull/16> It would be good to have this issue addressed upstream. I have just submitted these pull requests. I will provide an update if either pull request is merged (modified or unmodified). If neither repository makes any changes to address these questionable files then it may make sense for Guix to patch the cowsay package.