I should hope they all do, its for the best an animal doesn't actually breed because its wasting so many amazing animals' chances of finding much needed homes when they're in shelters, so its kind of annoying when people keep breeding more and more into the world... sorry to sound harsh

I couldn't help you out any further as I don't really agree with breeding like that so I've never looked into it personally. I'm sure others could give you advice but to be honest, an obvious thing to would ask around in your area, check local newspapers, even the Yellow Pages? lol seems a bit extreme but you never know!

Edit: My mistake! Read it completely wrong at the end lol! To answer your question properly, some may do! It all depends on whether they're trained vets and have a surgery too. Otherwise no, they would either take them to get neutered or advise strongly to get the animal to be neutered when they're adopted, and if they're a decent rescue then they would keep track and make sure they had been.