I don't know why the Zims/ISIS lists aren't accessible by the public anymore, they used to be. I think you can make requests for data on 'up to five species' at any time but that involves making specific enquiries and you can't just browse at your leisure anymore. Approaches direct to Zoos, particularly 'education' or 'PR' departments often result in muted responses, possiby because they've been told by the zoo not to give out such information/ they aren't sure if they should be divulging such information or they don't have it to hand. Having said that, I recently contacted a UK zoo with an enquiry about their specimens of a particular species, without much hope of anything but the usual brief reply, but they couldn't have been more helpful in providing a full answer for me. Rather unusual but very refreshing.