There was a bit of discussion just before g1 launched about whether
the fact that animals require no maintenance was a "hole" or not.
We looked at various ways to charge animal maintenance, but didn't
like any of them. Eventually we decided that there should be some
disincentive to large animal armies, such as combinations of animals
which fight and kill each other if they are kept together. This
hasn't been implemented yet, though.
-- Rich Skrenta <email@example.com>