How do I install Urchin 5 startup scripts on FreeBSD?

At install time a specific version of urchin4_daemons for the system should be created in the ~urchin/util subdirectory. You can edit the /etc/rc.local file (or create one if it doesn't already exist) and at the end of the file before any exit statement add these lines:

if [ -f INSTALLDIR/util/urchin_daemons ]; then
    INSTALLDIR/util/urchin_daemons start
fi

...and in the /etc/rc.shutdown script at the end, before the exit statement, add:

if [ -f INSTALLDIR/util/urchin_daemons ]; then
   INSTALLDIR/util/urchin_daemons stop
fi

Note:
In both these commands INSTALLDIR should be replaced by the full path to the Urchin installation.