Here some info I found online.
The Catskill Game Farm was opened in 1933 by Roland Lindemann, and was still owned by the Lindemann family, as Catskill Game Farm Inc. at the time of its closing. At first, it held only deer, donkys, and sheep. In 1958, the United States Department of Agriculture recognized Catskill as a zoo, and it became the first privately-owned venture to achieve such status. The collection was now allowed to grow more exotic and at the time of its closing played host to roughly 2,000 animals from over 150 species, imported from around the world.
The zoo spanned more than 370 hectares (914 acres), most of which was used to breed animals for other zoos worldwide. Only around 55 hectares (136 acres) was available for public viewing, and then only in the summer and autumn.