Glen...I don't think the zoo would let you do it...and I tend to think that they should not let you do it. I'd have to think longer about whether the test would work....but I don't think it would....probably too many variables. Also, it could be decades before there was a large quake close to that zoo (meaning, very close). I think a systematic observation of many animals at that zoo, along with many other zoos, would be better. It would have to be something measurable...for example...km/hour of pacing or something.
OK, after writing this, I have my doubts that: a: anyone would want to do this; b: that any clear signal would show up.
Chris