I installed them by running
tlmgr install cowfont --repository http://tlcontrib.metatex.org/2012
...which gave me:
tlmgr: package repository http://tlcontrib.metatex.org/2012
[1/1, ??:??/??:??] install: cowfont [656k]
tlmgr: package log updated at d:/programs/texlive/texmf-var/web2c/tlmgr.log
running mktexlsr ...
done running mktexlsr.
running updmap-sys ...
updmap-sys failed (status 1), output:
updmap is using the following updmap.cfg files (in precedence order):
d:/programs/texlive/texmf-config/web2c/updmap.cfg
d:/programs/texlive/texmf/web2c/updmap.cfg
d:/programs/texlive/texmf-dist/web2c/updmap.cfg
updmap is using the following updmap.cfg file for writing changes:
d:/programs/texlive/texmf-config/web2c/updmap.cfg
dvips output dir: "d:/programs/texlive/texmf-var/fonts/map/dvips/updmap"
pdftex output dir: "d:/programs/texlive/texmf-var/fonts/map/pdftex/updmap"
dvipdfmx output dir: "d:/programs/texlive/texmf-var/fonts/map/dvipdfmx/updmap"
pxdvi output dir: "d:/programs/texlive/texmf-var/fonts/map/pxdvi/updmap"
ERROR: The following map file(s) couldn't be found:
koeieletters.map (in d:/programs/texlive/texmf-dist/web2c/updmap.cfg)
Did you run mktexlsr?
You can disable non-existent map entries using the option
--syncwithtrees.
so that package doesn't seem to include the .map file, so I got it from here and after another texhash, re-ran the part that had failed:
updmap-sys --Enable Map koeieletters.map
update:
As the package doesn't contain any .sty or .fd files (yet), we have to do the necessary definitions ourselves:
\documentclass{scrartcl}
\usepackage[T1]{fontenc}
\DeclareFontFamily{T1}{CowFont}{}
\DeclareFontShape{T1}{CowFont}{m}{n}{<-> koeieletters}{}
\begin{document}
\usefont{T1}{CowFont}{m}{n}
stop stealing sheep
\end{document}
