When someone is intoxicated to the point that they can't make informed consent to have relations with another person, does that give the other person the right to just declare that consent plays no role and is absurd? No, the correct response to someone being unable to consent, is that it's an automatic no. The same should apply for non-human animals.

A chicken can't consent to their eggs being taken, so they should be left alone. A cow can't consent to being artificially inseminated, so they shouldn't be forcibly impregnated just so their milk can be stolen (another thing they can't consent to).

Oh and btw, I'm reticent to even mention this because it was only an appeal to authority in the first place, but the Vegan Society has materials on their site where they talk about why raising animals for their products is unethical - and the animals being unable to consent is part of that discussion.