That's humans for you. We exploit animals. Sad, I know, but what can we do? It's been a tradition in many places. Greyhound racing, etc.....those dogs are supposed to be human animals, yet they are kept in cages, albeit large in most cases. And when they're too old to race, they're on the adoption list. If no one adopts them, they're euthanased.
Sad, sad world.