It's doable depending on the exact breed, but it is more complicated than mixing other kinds of poultry and you need a LOT of space and more than one coop.
I have jumbo French Pearls that I've raised with chickens (I fact I've got six new ones being raised BY the chickens) and they get along decently. And by decently I mean the guineas don't treat the chickens any worse than they treat each oher: Guineas don't have any sort of subtlety when it comes to enforcing the pecking order.
However even if it goes well that first spring is a doozy. If you think young roosters are a handful they have nothing on the chasing / head butting / feather breaking antics of male guineas in breeding season. Even out of early spring they tend to behave more like a tiny feathered biker gang than poultry: they tend to stay is a group and there's a lot of swagger.
My chickens are used to them, but when I integrate new birds into the flock the guineas tend to scare the hell out of them: guineas don't like strangers, even other guineas. The only exception I've seen is when I let the broody hens raise chicks or keets: then the guinea's hazing is at a minimum.
You also may have trouble if you have any roosters. Guineas don't like certain rooster habits like mating in public or fighting out of season . I've seen guineas discipline roosters they think are out of line, and if a rooster picks a fight with a guinea he'll find out the hard way guineas tend to fight in packs.
