At its core I think that my ethic stance is best described as anti-realism. There's no intrinsic value; value is assigned by the subject. In turn, each individual (incl. me) assigns values due to a bunch of different factors: defending one's own interests, instinct (kin selection), culture/ideology, Realpolitik, or even on a whim.

Thus moral premises (or their absence - moral nihilism) are individual and arbitrary. I personally picked "weighted selfishness" and kin selection as two of mine. This leads to some sort of "rank", like: myself > my close relatives > other humans > other primates > other vertebrates > other animals > other living beings. Some individuals are sub-ranked higher due to their effect on individuals on higher ranks (e.g. someone's pet dog is above a stray dog, my lemon tree is above other non-animal living beings, etc.)

Beyond that it works like a "weighted utilitarianism" where life, general well-being and happiness of a higher category are more important than the ones of lower categories. It works symmetrically though - for example a jaguar hunting a human being is still moral, even if the jaguar was somehow intelligent. (And so is the self-defence of the potential human. Or of a pig against a human.)

Based on that: battery farm is for me less moral than free range, but still within acceptable morality - because it benefits beings high in my priority (humans) by a lot.

Animal lives matter a bit. Animals closer to us matter more. I'm not sure however if their simple existence has a positive "happiness" value, it's just referring to the life itself.