My first consideration is drainage. You want the coop and run to be as dry as possible, so position them where water does not run into them during a rainstorm. It helps if water drains away from them instead of toward them so if they get wet they can drain dry.
Predators can find your chickens no matter where you put the coop. You handle that by building a strong coop and a decent run, plus lock them up at night when most predators are most active.
Heat kills chickens. I’d opt for a well-drained place in the shade, especially protected from the hot afternoon sun.
