 In previous centuries, every city of any size had to have a slaughterhouse in a fairly central location, and animals mostly walked there themselves. You can imagine the noise, the smell, the runoff, and the street congestion caused by, say, a herd of cattle proceeding down Main Street, and understand why these facilities were not pleasant neighbors. But meat production had to be local, because the moment an animal was butchered, there was a race against the clock to get it cooked or preserved before it spoiled.