I'm pro free-ranging, though of course you must provide some protection against predators. Our initial plan was to keep our small flock in a very large pen. We have a huge fenced backyard but it was our own dogs that worried us most. To our surprise, our dogs were quite easily trained not to hurt the chickens. Now they help keep the chickens safe. Hawks are somewhat of a concern. But it makes our hens so very happy to range that I think it's worth that small risk. Several months now and so far, so good, knock wood.
Funny there is a hen that lives down the street and has thrived with no protection whatsoever for over 2 years now. She arrived one day at this guy's house, a stray or abandoned. He lets her roost in his garage in the winter. But she is penless, coopless, and rarely fed. I do worry about her, but she looks healthy enough. Mind you, this is a neighborhood full of coons, possums, skunks, and dogs. I've no idea how she survives.