With regard to sanctuaries, in the UK they are not governed in the same way as zoos are,why not, I don't know, so I am always wary of such places.
It's exactly the same over here in the United States. There are simply no government mandates or regulations surrounding animal sanctuaries. Literally, any layperson can start a "sanctuary"! They don't need to prove that they have the money, the training, the land, or even the resources to properly care for exotic animals, they can just begin accepting animals!
There
are private organizations that proclaim to provide guidelines for animal sanctuaries... but more often that not, they're run by the
very same people running the animal sanctuaries! Industries that attempt to police themselves tend to do a piss-poor job of it IMHO.
The question then is ,where do animals go when the sanctuaries are full?
I do believe that we just established
why sending any zoo animal to a self-proclaimed animal "sanctuary" is terrible idea. Ergo, for the surplus animals' sake, humanely killing them in their home environment at the zoo, instead of sending them on to parts unknown to face who knows what kind of treatment, is the more moral thing to do.
To cull surplus animals just because zoos want lots of baby animals, I think is morally wrong
Why do you think that any zoo would choose to cull an animal just because they "want lots of baby animals"? Where has the zoo that's the subject of this thread said that's their justification for culling twenty Guinea Baboons?
As I have previously mentioned, EAZA zoos seem to view that allowing their animals to have and raise their own offspring every year is more ethical than keeping the sexes permanently separated or on contraceptives for nearly their whole lives. Why
exactly do you think that's wrong? Sexual segregation can cause behavioral problems, while long-term use of contraceptives has been known to cause sterility.
There's no right or wrong answer here, just different cultures having differing views on animals.