I can consider that separately. With respect to whether those animals have rights, it is a nullity.
"Feelings" is not the source of rights. The moral contract is the source. Creatures incompetent to enter that mutual exchange between equals do not benefit, ever, unless a creature that *can* join is willing to extend the aegis of *their* rights over it. Which usually has a price. And limitations.
You can protect as many chickens as you can afford to keep. No more.