Raising Backyard Chickens?

I just moved onto a 30 acre farm and live next to my landlord who has a portable chicken coop that he moves around his 'side' of the property where all the hens are free range. He is allowing me to get chickens and ducks (we also have a small pond). Since we are on a lease I cannot build a permanent coop, if I were to build a portable chicken coop would my chickens join his flock or would they stay in our yard? I only want 3 but I want the eggs to be on my side of the property and not in his coop :)