In our world, there exists a Universal Declaration of Human Rights, to protect human beings and their rights to things like life, food, water, justice, freedom (for those who have not committed any crime), freedom of speech and protection from torture, bodily harm and murder. While this does not always work, having the Universal Declaration of Human Rights is definitely better than not having it.
Now, we need a legally enacted Universal Declaration of Animal Rights, protecting animals from cruelty, harm and unjust killing...
It is scientifically proven that animals are sentient; they think and feel just as truly as we do. They may not think to our level, or have our level of intelligence and communication, but they do think and feel. Koko the gorilla learned sign language. If an animal can learn to communicate with humans using a human-created language, does this not imply a great enough level of intelligence and sentience to warrant legal, worldwide recognition of animal rights? Animals also display emotions in varying ways. For instance, a dog wags their tail when happy (or when anxious), and tucks their tail between their legs and cowers when afraid. A pig will show what would seem to any caring animal lover as fear when being driven to a slaughterhouse. A pig was also scream when going into a slaughterhouse, or being slaughtered. A cow will bellow in grief and distress when separated from her calf. If she were a human, she would be crying physical tears, crying out loud in distress. Animals will also run away when afraid, scream and cry in pain and distress, help other animals (showing empathy and compassion), solve problems, seek affection and attention, let their humans know when they want feeding or playtime, and a mother animal has responsibility to care for her young, and she does this by nurturing, feeding and protecting them. She probably also loves them like a human mother would love her baby.
Despite all of this, animals are often treated horrendously by humans, often for ridiculously unnecessary reasons. They are hunted, shot down and torn apart for "sport". They are trapped, gassed, poisoned, beaten to death, electrocuted, have their necks broken, are killed by lethal injection and skinned alive so that humans can wear their fur for fashion's sake. They are debeaked, have their ears and teeth cut, are castrated without anaesthetic, forced to live their lives in squalor, only to be driven, sometimes going hours without food or water, and are then forced towards their deaths. They are then stunned using gas chambers (where they burn on the inside. This is akin to what the Nazis did to their victims), electric tongs, electrified water baths, captive bolt guns, and then have their throats cut to become our dinners. They are experimented on and subjected to extreme cruelty in the name of science, research and testing. They are taken from their homes, kept in chains and beaten using whips and bull-hooks for our entertainment. They are drugged, muzzled, beaten and forced to run on dangerous tracks so that people can gamble money on them and watch them race. They are kept chained, beaten, starved, attacked and forced to fight and attack for people's sick entertainment and gambling. They are kept chained, starved, beaten, hit, kicked and abused by people. Stray and feral animals are poisoned, beaten and shot to death, and also have acid thrown on them. They are subject to neglect, abandonment and killed at shelters in the millions. They are forced to work carrying heavy loads for people. They are subject to the cruelties of the dairy industry (having their calves taken away, the male calves being shot or raised for veal or beef, forcible impregnation that can cause serious injuries, suffering from mastitis, injected with hormones and antibiotics and sent to slaughter at only a small fraction of their natural lifespans). The male chicks on egg farms are gassed or shredded alive, and the laying hens are sent off to be slaughtered and made into low-grade meat products when they are no longer useful.
All of this could be drastically reduced if a Universal Declaration of Animal Rights was written and passed into international law to protect them. Here's what such a declaration could entail:
* Ensuring that all animals have a right to life, to be fed, given water, given sufficient living quarters, affection, love and exercise, to not be unnecessarily subjected to harm, and to not be killed unnecessarily killed.
* An end to all hunting, except that which is absolutely necessary for human survival and is done respectfully.
* An end to the fur trade.
* An (eventual) end to all animal farming and slaughter, encouraging people, as much as possible, to go vegan and providing huge grants of money and subsidies to farmers who switch to growing crops, fruits and vegetables for people to eat, and proving huge sums of money to those who work on developing faux meats and lab-grown meat.
* An end to the shooting of animals for sport.
* An end to all unnecessary animal testing and research.
* An end to all lethal pest control.
* A ban to all bullfighting, a ban on the cruelties of greyhound and horse racing, an end to horse fighting and greatly enforcing bans on dog-fighting and cock-fighting.
* A ban on the mistreatment of animals like horses, ponies, donkeys, mules, hinnies, elephants and camels for riding and work.
* An end to breed-specific legislation worldwide.
* A worldwide ban on commercial dog breeding, a international provision of the money and other factors necessary for all shelters, rescues and pounds to be no-kill, and a ban on the unnecessary killing of animals in shelters, pounds and rescues.
* Legal protection of strays and feral animals.
* Legally recognising all sentient animals as nonhuman persons, not property.