I have got all my pets from SoCal shelters and they can't leave the shelter without being spayed/neutered.
Disclaimer, our current three cats were "found" by my wife through various friends and family.
Our current lineup (all neutered)
When looking for cat #3 {Marshal} I was looking at the shelter websites and you are right 40% pit bull, 40% chiwawa... sad, so sad.
It is a hard world we live in.