I have a whole menagerie of animals and the turkeys are the easiest! They are docile and don't need much of a fancy shelter. When our babies were only a few weeks we turned them loose in the yard and they scavenged for bugs and plants and put themselves to roost in a tree at night - but never ventured too far away from the coops.
Remember turkeys are native to the north american woods and tolerate the elements really well.
Although I don't worry at all about predators, the dogs are really good about keeping the yard safe and they would never hurt my birds. If I didn't have the dogs I would definently want to cage them for safety.