Guineas -- I've heard the do not like snow! Me neither
They eat all kinds of bugs.....and worms from your garden plants. While they do scratch, it's not like a chicken, far less. They can eat at the garden fruit but, normally not much as they are far more interested in the bugs/worms. Many say they never have squash bugs with them around. Grasshoppers, ticks, fruit tree worms, etc. and they chase flies! Reportedly they will attack snakes and eat those they successfully hit on -- group effort? -- as well as small rodents. Well, they do tend to stay in a group, even moving through a pasture area. Great "watchdogs" who alert to unusual thinigs (often unwanted alerts but --) be it a person, animal, etc. They are reported to be very good at alerting to overhead threats, so often keep chickens safer from hawks, etc.
That said, they are far more independent and less desiring of human contact than chickens. They can be trained to return to a coop at night but, also like to roost in trees. They do lay eggs, tasty ones, but do not use nest boxes like chickens. The prefer a "hidden" area. Easter egg hunt each day. Can be controlled by penning until later in day, making hidden areas outside of regular nesting for them, etc.
Won't replace my cats but, a nice addition to the hens AND boy did I have grasshoppers this year!! One of my barn cats is a devout climber, so she has convinced the barn swallows that they can't nest in the equipment shed as she patrols the rafters -- therefore their nests! -- I have to control that before next spring........hmmmm.........mosquitos, ya know?