This brocket deer mazama americana is definitely like the ones in mexican zoos and i think it was acquired from Africam safari park in Puebla, which is AZA accredited and has a very good breeding record for these deer. Nice to see them doing well.
In Latin America various zoos breed brocket deer, but it seems that in the US they are very rare, perhaps only in Phoenix and brownsville zoos mentioned here. I do not know of their situation in europe. They are very nervous and shy animals, so they need vegation to hide away at times. There are various good photographs of brockets in the zoochat galleries.
I only saw two. This one was on the main island and another one was on the narrow strip of land that runs along the far wall (next to the dirt walkway that goes around spectacled bears). Since that strip of land is not connected to the main island I can only assume it swam across.
I dont know the exact number of individuals in captivity, what i do know is that 3 of 10 living brocket deer species are currently in captivity and those species are the Gray brocket, Merida brocket and the more common Red brocket, there are currently no Gray brockets or Merida brockets in the United States but Phoenix Zoo and Gladys Porter Zoo have Red brockets, the Los Angeles Zoo , Louisiana Purchase Zoo, Cologne Zoo, and Leipzig Zoo used to have Red brockets but they no longer have them, The Los Angeles Zoo also had Gray brockets but no longer has them, In fact there are no Gray brockets in zoos outside there home range except in 1 spanish zoo, they used to have Gray brockets at Tierpark Berlin, Berlin Zoo, Krefeld Zoo, Cologne Zoo, Rotterdam Zoo, London Zoo and Knowsley Safari Park. There used to be Merida brockets at the London Zoo, but now Merida brockets are only at zoos in there home range. I hope this info helps.