I would rank this as the worst zoo I've ever visited without much thought. It's owners are, I understand, getting on a bit and I think the zoo keeps going through sheer inertia. It's tucked away on a little local street and is overrun with domestic (feral?) cats. Fascinating place to visit (once) in many ways but I will not be hurrying back.
It's a shame really as this "zoo" seems to have a nice, wooded setting. For example, here you could probably have pretty good porcupine enclosure if you got rid of the concrete prison, securely fenced in that piece of land behind it and let the porcupines have real trees to climb.