Hi GarthRyan,
My experience with raising my backyard flock of New Guinea Fowl and Chickens, Ducks and Geese together has been interesting to say the least. My backyard flock free-range during the day and they all coop together at night. The Guinea will explore boundaries that contain the chickens because they can fly much better than all the other birds, but each night they return to the safety of the coop. Guinea are well equipped to escape dangerous ground predators, including neighboring dogs and overhead hawks and eagles. They are great watchdogs. They will protect the flock by alerting to danger. A broody Silkie hen raised our 3 young (week old) New Guinea keets until fully feathered. Once she raised them and they were on their own, we purchased 2 more Guinea hens about the same age. The five of them hung out with the Silkies during the day, sometimes exploring on their own, but most of the time stayed in the back yard for the majority of the day. Everything was going well until I rehomed a few of "their" Silkie family members, The very moment they realized those chickens were gone and new chickens had arrived, the pecking order changed. The Guineas became the head of the pecking order. Now they attack every new bird, regardless of age, sex or breed. They chase off mothers brooding their young, and have even chased our young cats who are experiencing the outdoors for the first time. They pluck out the feathers of new birds, regardless of rooster or hen and chase them off into the sticky bushes. After loosing one young cockerel to the vast woods never to be found again and getting myself all scraped up by blackberry to retrieve a few roosters from the brambles, did I decide that I had to intervene. The adult Guinea will take on everything that is new to the property so I now oversee all new introductions for up to a week. I run off the Guineas and keep the newbies in a large pen for a period of time while everyone gets acquainted. I continue to oversee for the first few days when the newbies are then released into the freedom of the backyard flock. Only on occasion do I then need to intervene, and it's usually someone chasing off another over food at that point. I enjoy my Guineas and believe they are a great addition to a back yard flock. I don't believe they would do well confined in a chicken run, because they would just pace back and forth endlessly looking for a way out, but if the could be let out each day to free range, they would coop with your chickens at night if you trained them to do so from the start. Note: There are a few occasions where they refused to coop at night and in those cases, we are usually able to catch them and place them in the coop (we grasp their wings and bring them together behind their back and then use one hand to hold both wings fairly close to the back while transporting or if you grab them any other way the Guinea will flare and scream and release all their feathers and you might end up scratched up and left empty-handed... lol... and the poor Guinea will be missing many-many feathers). Others might have a different experience, but for the most part everyone in my flock gets along with proper introductions. Happy Raising!