What Mike K said, the portable coop can be a great setup, friends who run a "natural" farm in MI when we worked there had a portable coop that was built on an old hay wagon (up off the ground). They experienced very little loss and they had all the typical predators aerial and terrestrial on their acreage.
Now, if you don't close the coop door at night (which happens) it is game on and you are going to lose big depending on the critter that gets in there.
They also raised turkeys each year and had portable hutches that allowed a "free range" experience without completely turning them loose to get into trouble.
We had chickens on the farm I grew up on along with geese and ducks and other farm stock. They were allowed to do as they wanted and we took eggs from the ones using nest boxes inside the barn in a coop that was left open.
Dogs got some, fox got others, weasels on occasion, however, we always had more chickens and rarely did we add to them in the 18+ years that I paid attention and was on site...
On the market end of things, there are more and more folks for a variety of reasons (raising their own food, teaching their kids where food comes from, marketing to farm to table places), the folks that can figure out innovative ways to help these folks raise their farm stock in a free range situation will make some money.
Some of these issues are old and time tested and we all know it is an uphill battle that can seem more like a hobby than something you "win" at, however folks are going to keep doing it so why not think outside the box and try to create something that works.
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Justin