I like how le ebic contrarian snark has become so commonplace and incestuous on the internet that people are unironically reverting back to literal Diogenes "arguments".
Ignoring that having egg-producing equipment also differentiates hens from roosters, Rowling using the term "YOU" when stating her claim should point to the fact that she's not talking about fucking animals.
In what possible context would the preface of "If you have x y z" be used when referring to anything other than people? Are there chickens reading twitter?
It's like if Rowling said "If you weigh 30 stone, you're a very unhealthy person" and some retard replied to her with an image of a small car and said "behold, a very unhealthy person!" Like wow dude you sure showed her.