biophiliac
Rest in Peace 1953-2021
not as much as chickens because they 'free range' in the sky! lol.DH poo-poohed the idea of quail, but got totally excited when I mentioned homing pigeons.
How much space do they need?
How big of a loft totally depends on your goals with them.

Rule of thumb is 2 cu ft per bird. It is good to have at least 2 sections(which I do not) so you can separate genders or flyers from breeders.