To add to others' comments, having animals increases a farm's productivity, since a lot of plant material is indigestible for humans. So they wouldn't have been

To add to others' comments, having animals increases a farm's productivity, since a lot of plant material is indigestible for humans. So they wouldn't have been vegan. Chickens and pigs are omnivourous and will eat all sorts. Ruminants such as cows or goats can convert inedible grass and other cellulose-rich material into milk and meat.