For centuries, the legal system has viewed animals through a single, rigid lens: they are property. In the eyes of the law, a dog is legally similar to a toaster or a car—an object to be owned, bought, and sold. If you damage someone else’s dog, you are liable for the cost of the "object," but the dog itself has no legal standing to sue for its pain.
The result is a hybrid system. We are unlikely to ban zoos or slaughterhouses entirely in the next 50 years (rights). But we are rapidly moving toward massive cage-free requirements, slower growth broiler chickens, and the end of cosmetic testing (welfare). For centuries, the legal system has viewed animals
Farm Animal Welfare Council. (1979). The Five Freedoms . London: FAWC. slower growth broiler chickens