Don't chickens need vitamin D from sunlight?You may want to double check the standards for space per bird. I do not think their safety around the pool is much of a concern. My chickens are free range with three ponds in the immediate vicinity and nobody has fallen in yet. And unless you have planters at the waterline i do not see chickens spending much time wondering around the concrete apron. However, you are going to be in shock when you see poop in other places you can not imagine. Some folks will say you have to let them out in order for them to be happy. this is primarily a wives tale. Since i became physically impaired right after getting my coop built my chickens had to stay in the coop for a few months. They never tried to get out even when the door was opened to clean or feed. However once you let them out they will forever more want to be let out.
They certainly need access to light to lay.