How so? As long as it is cleaned properly and often enough (as in every day), and there is good air circulation/ventilation, it should be manageable.
Some might say definitely have all the mammals outside but you have to consider the endemic species aswell.I have heard of stories where meerkats were being picked from the outdoor enclosure by large raptor birds. Also what happens if something gets into the enclosure and spreads diseases such as something like a fox transmitting rabies to another canine. Things like this can happen so easy. Back in the 70s every Siberian Tiger at Dublin Zoo had to be euthanised because of a TB outbreak supposedly transferred from a feral cat. if mammals are to be kept outside the enclosure must not only be suited for keeping the zoo animal in but also the native species out.
