Animal Ethics relates to how we ought to treat Non-Human Animals. Current treatment of animals is potentially a moral emergency. Though these discussions are underway.

“There is no fundamental difference between humans and animals in their ability to feel pleasure and pain, happiness, and misery.”
- Darwin

The question is not, 'Can they reason?' nor, 'Can they talk?' but rather, 'Can they suffer?'
- Jeremy Bentham

Animal Ethics covers a lot of ground, including but not limited to:
Animal Rights, Vegetarian/Veganism, Diet, Effectiveness of these methodologies, Nutrition, Industrial Meat Production, Sentience, History, Animal Welfare, Speciesism, Other things?

(If your post relates to Non-Human Animals and their internal states, it probably belongs here)

For Further Info, Here is an introduction by Peter Singer

WARNING:
Those who play in these woods should dance with care, the forest is dense here, it is easy to trip on a root or your foot.

Unfortunately, there are few topics you less want to come up at a non-rational dinner party than Animal Ethics as it can be highly contentious.
Before engaging with this section of LessWrong, weather you believe Non-Human Animals deserve rights or not, please take a deep breath... and remember your training as a rationalist.