The answer depends on how you want to test for self-awareness. For a long time it was defined via the mirror test [0], but there is a lot of evidence that the test isn't a great test for many animals (eg where vision isn't one of their primary senses). As far as I know, no "food" animals have passed the mirror test; a number of aquatic mammals, primates, and birds (none of which are eaten commonly in the US) have, and one species of fish.

Personally, I am of the opinion that testing for self awareness is very difficult and its not clear why that's the cut off for where we stop eating things to begin with. Clearly the animals we farm and eat are capable of feeling pain, and many of them are very intelligent. Pretending that we would respond to the news that eg pigs had passed the mirror test by no longer eating them seems farcical to me.

[0] https://en.wikipedia.org/wiki/Mirror_test

[1] https://en.wikipedia.org/wiki/Animal_consciousness

The only proxy we have for measuring self-awareness is "responds in a way that maps to human behaviour in X scenario"—e.g. things like the mirror test—which, while it's the best we've got, isn't very compelling given the diversity we observe even in primates.

Without any convincing evidence in either direction, I find it perplexing that people seem to default to asumming the negative (i.e. the more convenient assumption)

What's your criteria? Theory of mind? IMO if something is at the level that they can experience pain, then they are conscious enough to suffer.

Given that we don't even understand what consciousness is in humans, this is a sticky question. But the short answer is yes, and not only mammals, either. See https://en.wikipedia.org/wiki/Animal_consciousness, specifically the bit about the Cambridge Declaration.