To a degree, yes, however, if you don't afford them some night time protection, they will be picked off by predators and you'll have to "restock" them periodically. A quarter horse farm down the street from me started with 20 guineas about a year ago. They are down to 3 now, mainly because the guineas love to get into the road and are always hit by cars, but also from our large predator base here.
They won't find much to eat in winter, though.
They won't find much to eat in winter, though.