Got it. Yeah it's a tricky thing - I've seen stories about rooftop chicken setups in Seattle but I think it would be a lot of work to maintain, having to truck litter up and down from there and constantly checking on the integrity of the roof under the set up.The rooftop patio is private and belongs to me only. It is the top floor of a detached townhouse I am purchasing. I would not put my chickens up on a communal rooftop, lol.
Thanks everyone for your input - this has been incredibly insightful. I am leaning towards rooftop chickens not being as feasible as I dreamed, or at least extremely difficult to maintain for both myself and the wellbeing of the girls. We'll have to think of a plan B....
Only real plus side is obviously ground based predators wouldn't get to the birds, I guess.