In simple, Yes.
It all depends on what the aims of the zoo will be and what your own aims are; Why open a zoo if YOU won't enjoy looking after what is there?
I know a man who opened a birds of prey centre 17 years ago and when opened he started with about 30 birds and his two kids and wife, and now he has 25 staff, many volunteers (Myself being one) now over 150 birds between over 50 different species. In recent years he has added things such as otters, meerkats, huskies, a reptile house with about 10 species, camels and also cheetahs!!
It's not like he was a millionaire when he started, he was just a normal guy why had some birds and wanted to educate people about them... Now look where he is!
Any more questions on opening a zoo, please feel free to send me a message