I don't think there is that much of a difference, just as I think it's not very ethical of us to say that we can't eat dogs because it's unethical, but chickens are a-okay. They are just another species living on this planet. They may not be as smart, they also have no play in deciding what's the intelligence level they need to be at before humans can stop considering them food.
We, humans, decide what we can and cannot eat. And some of us still hunt animals just for sport or for their horns and fur, even if they are in that "higher intelligence" bracket.
But hopefully as our societies evolve, and technologies also evolve to at least give us a choice between having to eat a chicken, and having to eat manufactured/replicated meat, we'll learn to give up on these, too.
There really isn't a difference but we're all hypocrites the vast majority of the time, probably without even knowing it. Food is just too much of a part of us, we don't want to give it up!
I see it as inevitable that artificial meat replaces wholesale slaughter with actual animal rights. Let's just admit that most of the world (myself included) won't stop eating meat until that artificial stuff is here and focus on the easier topics first.
We, humans, decide what we can and cannot eat. And some of us still hunt animals just for sport or for their horns and fur, even if they are in that "higher intelligence" bracket.
But hopefully as our societies evolve, and technologies also evolve to at least give us a choice between having to eat a chicken, and having to eat manufactured/replicated meat, we'll learn to give up on these, too.