Wisent were bred at the zoo many times ... yes, they were a phase-out species (now complete). In order to help track births, the studbook issued two letters to each holding institution, and all wisent born there had to have names beginning with those letters. Toronto was CO - Colette, Connie, Cobey, Cologne, Contessa, Conrad ... those are the six that I can remember (Conrad is Winnipeg's breeding male).
I believe the wood bison moved to the domain a while ago, and I suspect the wisent exhibit will remain empty in preparation for the next phase of the North Site redevelopment (otherwise, they will simply move other hoofstock over).
In Indo, they are building two aviaries at the entrance ... separate holding spaces are in desperate need for the pavilion's birds ... some have had issues breeding in the free-flights, and others have taken to dive-bombing keepers and visitors (not such a good thing). I'm not sure which species will be moved in when they are complete.