Well, no, they won't be able to forage enough if it's a small pasture. They do need extra feed. I'm guessing that the more you do to get them forage the better

Well, no, they won't be able to forage enough if it's a small pasture. They do need extra feed. I'm guessing that the more you do to get them forage the better the meat and eggs will be, for instance larger pasture and making sure your other animals leave plenty of dung around.