I would say that anything which is both deterministic and fundamentally unpredictable by humans can be said to have something like "Free Will", which I think includes a lot of non-conscious systems as well as human beings. The weather, flocks of birds, river flows, sunspot activity, etc -- really any kind of chaotic system -- which is not the same thing as saying it's random.

But it's also a self centered definition, because I think a being with vast computational power and perfect knowledge of the current state of a chaotic system might not see it as free.