I forgot to mention that the chicken's, ducks, cow, goats and dog come into the barn to roost/sleep for the night. And these animals are allow
freedom so they help provide for themselves by foraging in different areas, thereby allowing the ground to recover and reducing any feeds that are provided.
I don't have the time just now to cover all the details, suffice it to say that any animal arrangement can work if you have a plan to deal with the issues it presents. There isn't one right way.
If you would like to forgo the time and expense of fencing of your chicken range area, then plan for day time predictors such as neighbor's dogs and cats, and maybe a fox if it applies. If you roost them in a contained house you shouldn't have to worry about raccoons and other night time predators. I have friends who allow their birds to roost in the open, and it works for them, but again they deal with the issues that their setup brings.
In fact of all my friends I can think of just now none of us have the same set up, and none of us have any more than the the rare loss, indicating something needs addressed to tighten the system.